nanoscale ferroelectrics and...
TRANSCRIPT
Nanoscale Ferroelectrics
and MultiferroicsKey Processing and Characterization Issues,
and Nanoscale Effects
Edited byMiguel AlgueróJ. Marty Gregg
Liliana Mitoseriu
VOLUME 1
Nanoscale Ferroelectrics
and MultiferroicsKey Processing and Characterization Issues,
and Nanoscale Effects
Edited byMiguel AlgueróJ. Marty Gregg
Liliana Mitoseriu
VOLUME 2
Nanoscale Ferroelectricsand Multiferroics
Nanoscale Ferroelectricsand Multiferroics
Key Processing and Characterization Issues,and Nanoscale Effects
VOLUME I
Edited by
MIGUEL ALGUEROJ. MARTY GREGG
LILIANA MITOSERIU
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Library of Congress Cataloging-in-Publication Data
Names: Alguero, Miguel, 1969- editor. | Gregg, J. Marty (John Marty), 1969- editor. | Mitoseriu, Liliana, editor.Title: Nanoscale ferroelectrics and multiferroics : key processing and characterization issues, and nanoscale effects / [compiled
by] Miguel Alguero, J. Marty Gregg, Liliana Mitoseriu.Description: Hoboken : John Wiley & Sons, Inc., 2016. | Includes bibliographical references and index.Identifiers: LCCN 2015042479 (print) | LCCN 2015046191 (ebook) | ISBN 9781118935750 (cloth) | ISBN 9781118935675
(ePub) | ISBN 9781118935705 (Adobe PDF)Subjects: LCSH: Ferroelectric devices. | Nanoelectromechanical systems.Classification: LCC TK7872.F44 N36 2016 (print) | LCC TK7872.F44 (ebook) | DDC 621.381–dc23LC record available at http://lccn.loc.gov/2015042479
A catalogue record for this book is available from the British Library.
ISBN: 9781118935750
Set in 10/12pt Times by Aptara Inc., New Delhi, India.
1 2016
Contents
VOLUME I
List of Contributors xviiPreface xxiii
Introduction: Why Nanoscale Ferroelectrics and Multiferroics? xxvMiguel Alguero, J. Marty Gregg, and Liliana Mitoseriu
PART A 1
Nanostructuring: Bulk
1 Incorporation Mechanism and Functional Properties of Ce-DopedBaTiO3 Ceramics Derived from Nanopowders Prepared by the ModifiedPechini Method 13Adelina-Carmen Ianculescu, Daniela C. Berger, Catalina A. Vasilescu, MariusOlariu, Bogdan S. Vasile, Lavinia P. Curecheriu, Andreja Gajovic, andRoxana Trusca
1.1 Why Cerium-Doped BaTiO3? 131.2 Sample Preparation, Phase and Nano/Microstructural Characterization 18
1.2.1 Powders 181.2.2 Ceramics 22
1.3 Dielectric Properties 301.4 Raman Investigation 371.5 Conclusions 39Acknowledgments 40References 40
2 Synthesis and Ceramic Nanostructuring of Ferroic and MultiferroicLow-Tolerance-Factor Perovskite Oxides 44Teresa Hungria, Covadonga Correas, and Alicia Castro
2.1 Introduction 442.2 Synthesis of Perovskites Oxides 47
vi Contents
2.2.1 General Information on the Preparation of Low-tolerance-FactorPerovskite Oxides 47
2.2.2 Mechanochemical Activation and Mechanosynthesis Applied toLow-Tolerance-Factor Perovskite Oxides 48
2.3 Processing of Ferroic and Multiferroic Materials: From the CeramicMethod to the Current Assisted Methods 542.3.1 SPS Applied to the Preparation of Ferroic Ceramic Materials 60
2.4 Combination of Mechanosynthesis and Spark Plasma Synthesis: TheRight Track to the Nanoscale in Ferroic Materials 62
2.5 Conclusions 63Acknowledgments 64References 64
3 Core–Shell Heterostructures: From Particle Synthesis to Bulk Dielectric,Ferroelectric, and Multiferroic Composite Materials 72Vincenzo Buscaglia and Maria Teresa Buscaglia
3.1 Introduction 723.2 Liquid-Phase Synthesis of Core–Shell Particles 74
3.2.1 Controlled Assembly of Preformed Nanoparticles 743.2.2 Precipitation 75
3.3 BaTiO3@polymer Particles and Composites 773.4 Inorganic Core–Shell Particles with a Ferroelectric Core 783.5 Multiferroic Core–Shell Particles and Composites 833.6 Conclusions and Outlook 90References 92
4 Modeling of Colloidal Suspensions for the Synthesis of the FerroelectricOxides with Complex Chemical Composition 100Gregor Trefalt, Bosiljka Tadic, and Barbara Malic
4.1 Introduction 1004.2 Solid-State Synthesis 1024.3 Colloidal Interactions and Aggregation 103
4.3.1 DLVO Theory 1034.3.2 Modeling of Aggregate Formation and Their Structure 105
4.4 Aggregation in the Three-Component System 1064.5 Applying the Modeling Results to Enhance Properties of Ferroelectric
Complex Oxides 1094.5.1 PMN Synthesis by Controlled Aggregation of Reagent
Particles 1094.5.2 PMN–PT Synthesis by Controlled Aggregation of Reagent
Particles 1104.6 Conclusions and Outlook 112Acknowledgments 114References 114
Contents vii
Nanostructuring: Thin Films
5 Self-Assemblage and Patterning of Thin-Film Ferroic Nanostructures 118Theodor Schneller
5.1 Introduction 1185.2 Short Survey on Classical Top-Down Approaches 1195.3 Non-invasive Procedures 121
5.3.1 Nanomask Techniques 1245.3.2 Direct Self-Assembly of Ferroelectric Nanostructures 1265.3.3 Nanoseeds Assisted Growth 131
5.4 Embedded Ferroelectric Nanograins 1355.4.1 Embedded Lead Titanate-Based Nanograins 1365.4.2 Further Embedding Concepts 137
5.5 Conclusions 139References 140
6 Thin-Film Porous Ferroic Nanostructures: Strategies andCharacterization 147Alichandra Castro, Paula Ferreira, Stella Skiadopoulou, Liliana P. Ferreira,Margarida Godinho, Brian J. Rodriguez, and Paula M. Vilarinho
6.1 (Nano)Microelectronics Considerations 1476.2 Ferroics and Nanoferroic Structures 1486.3 Meso- and Nanoporosity in Advanced Functional Materials 1516.4 Nanoporosity in Ferroelectric Thin Films 153
6.4.1 Lead Titanate (PbTiO3) – Nanoporous and Nanopatterned ThinFilms 153
6.4.2 Lead-Free Ferroelectric and Single-Phase Multiferroic – BismuthFerrite 156
6.5 Looking Ahead 158Acknowledgments 160References 160
7 Low-Temperature Photochemical Solution Deposition of Ferroelectricand Multiferroic Thin Films 163Christopher De Dobbelaere, An Hardy, Marlies K. Van Bael, Inigo Bretos,Ricardo Jimenez, and M. Lourdes Calzada
7.1 Introduction 1637.2 Low-Temperature Processing of Ferroelectrics and Multiferroics 1657.3 Low Environmental Impact Precursor Chemistry 1657.4 Aquous Solution–Gel Precursors 166
7.4.1 Metal Ions in Water 1667.4.2 Gel Formation and Decomposition 1697.4.3 UV Activity 170
viii Contents
7.5 Photosensitive Sol–Gel Precursors 1717.5.1 Addition of UV-Absorbing Molecules to the Precursor Solution 1727.5.2 Synthesis of Highly Photosensitive Metal Complexes 175
7.6 Photochemical Solution Deposition (PCSD) 1787.6.1 Working Principle 1787.6.2 Low-Temperature Ferroelectric Oxide Films Prepared from
Photosensitive Sol–Gel Precursors 1827.6.3 Low-Temperature Ferroelectric and Multiferroic Oxide Films
Prepared from Aqueous Photochemical Solution Deposition(Aqueous PCSD) 185
7.7 Final Remarks 190References 191
Nanostructuring: Fibers and Wires
8 Synthesis and Properties of Ferroelectric Nanotubes and Nanowires:A Review 200Vincenzo Buscaglia and Maria Teresa Buscaglia
8.1 Introduction 2008.2 Synthesis of Ferroelectric Nanowires and Nanotubes 202
8.2.1 Direct Growth from the Liquid Phase 2028.2.2 Templated Growth 2088.2.3 Topochemical Solid-State Reactions 2118.2.4 Electrospinning 2138.2.5 Focused Ion Beam Lithography 213
8.3 Crystal Structure, Phase Transitions, and Ferroelectric Properties 2138.4 Applications 219
8.4.1 Nanogenerators for Energy Harvesting and Other Devices 2198.4.2 Dielectric Composites and Other Applications 221
8.5 Summary and Conclusions 222References 223
9 Fabrication of One-Dimensional Ferroelectric Nano- and Microstructuresby Different Spinning Techniques and Their Characterization 232Tony Lusiola and Frank Clemens
9.1 Introduction 2329.2 Fiber Synthesis 233
9.2.1 One-Dimensional Nanostructures 2339.2.2 One-Dimensional Microstructures 236
9.3 Investigation of Nanostructure, Microstructure, and Phase Composition 2409.3.1 Microscopy 2419.3.2 Phase Composition 243
9.4 Investigation of Mechanical Properties 2459.4.1 Characterization of Nanowires/Fibers 2469.4.2 Characterization of Microfibers 248
Contents ix
9.5 Ferroelectric Characterization 2499.5.1 Characterization of Nanowires/fibers 2509.5.2 Characterization of Microfibers 252
9.6 Applications 2559.6.1 Potential Applications for Nanowires 2559.6.2 Applications for Microfibers 258
9.7 Summary and Outlook 259References 260
PART B 269
Characterization (of the Nanostructured Materials): Crystal Structure
10 Structural Characterization of Ferroelectric and MultiferroicNanostructures by Advanced TEM Techniques 275Etienne Snoeck, Axel Lubk, and Cesar Magen
10.1 Introduction: Advanced TEM Techniques for the Analysis ofFerroelectric and Multiferroic Materials 275
10.2 Transmission Electron Microscopy 27610.2.1 TEM and HRTEM Basics 27610.2.2 TEM and HRTEM Imaging of Ferroelectrics 280
10.3 HAADF–STEM Structure Determination 28810.3.1 Basics of HAADF–STEM Imaging 28910.3.2 Solid-State Properties 29410.3.3 Case Studies 297
10.4 Electron Energy Loss Spectroscopy 30710.4.1 EELS Basics 30710.4.2 EELS Applications in the Characterization of Multiferroics 310
10.5 Future and Challenges 317References 319
11 Raman Spectroscopy of Nanostructured Ferroelectric Materials 325Marco Deluca and Andreja Gajovic
11.1 Introduction 32511.2 Raman Spectroscopy Fundamentals 326
11.2.1 The Raman Effect 32611.2.2 Selection Rules 32811.2.3 Phase Transitions 329
11.3 Raman Analysis of Relaxors 33111.3.1 Lead-Based Relaxors 33311.3.2 Lead-Free Relaxors 34011.3.3 Wrap-Up: Raman Analysis of Relaxors 351
11.4 Raman Analysis of Nanostructured Ferroelectrics 35211.4.1 Ferroelectric Nanostructured Ceramics 353
x Contents
11.4.2 Ferroelectric 2D Nanostructures 35711.4.3 Wrap-Up: Raman Analysis of Nanostructured Ferroelectrics 358
11.5 Tip-Enhanced Raman Spectroscopy (TERS) of NanoscaleFerroelectrics 359
11.6 Summary 362Acknowledgments 363References 363
12 Neutron and Synchrotron X-Ray Scattering Studies of Bulk andNanostructured Multiferroic and Ferroelectric Materials 375Evagelia G. Moshopoulou, Pascale Foury-Leylekian, Katharine Page,Celine Doubrovsky, Martha Greenblatt, and Alan J. Hurd
12.1 Introduction 37512.2 Synchrotron X-Ray and Neutron Facilities for Structural
Characterization of Ferroelectrics and Multiferroics 37812.3 Crystal Structure of NdMn2O5 in Powder and Single Crystalline Forms 381
12.3.1 Multiferroelectricity in RMn2O5 Compounds 38112.3.2 Synthesis of NdMn2O5 38312.3.3 Synchrotron X-Ray Powder Diffraction Data Collection 38412.3.4 Synchrotron X-Ray Powder Diffraction Data Analysis 38412.3.5 Results 38512.3.6 Discussion 385
12.4 Neutron Total Scattering Investigations of the BaTiO3@SiO2Nanocomposites 39012.4.1 Neutron and Synchrotron X-Ray Probes for Nanostructure
Determination 39012.4.2 Ferroelectricity in BaTiO3 39212.4.3 Total Neutron Scattering Data Collection 39312.4.4 Total Neutron Scattering Data Analysis 39412.4.5 Results and Discussion 394
12.5 Concluding Comments 395Acknowledgments 395References 396
Characterization (of the Nanostructured Materials): Domains
13 Advanced Characterization of Multiferroic Materials by Scanning ProbeMethods and Scanning Electron Microscopy 400Michael R. Koblischka and Anjela Koblischka-Veneva
13.1 SPM-Related Methods in Advanced Materials Research 40013.2 Magnetic Force Microscopy (MFM) and Related Methods 403
13.2.1 Magnetic Imaging 40313.2.2 Magnetic Force Microscopy (MFM) 40613.2.3 Further Developments (HF-MFM, MRFM) 406
Contents xi
13.3 Electrostatic Force Microscopy (EFM) and Piezo Force Microscopy(PFM) 40813.3.1 Electrostatic Force Microscopy (EFM) 40813.3.2 Piezo Force Microscopy (PFM) 408
13.4 Scanning Tunneling Microscopy (STM) and Related Methods 40913.5 Imaging of Crystallographic Orientations (SEM/EBSD) 412
13.5.1 EBSD Technique 41213.5.2 Examples of EBSD Measurements on Multiferroics 41613.5.3 EBSD Analysis of a Composite Multiferroic 41813.5.4 Future Directions 425
13.6 New Developments in the Field of EBSD 42613.6.1 3D EBSD 42613.6.2 Transmission EBSD (t-EBSD) 427
References 428
14 Electrostatic and Kelvin Probe Force Microscopy for Domain Imagingof Ferroic Systems 435Brian J. Rodriguez
14.1 Introduction 43514.2 Electrostatic Force Microscopy and Kelvin Probe Force Microscopy 438
14.2.1 Electrostatic Force Microscopy 43814.2.2 Kelvin Probe Force Microscopy 438
14.3 EFM of Ferroelectric Materials 43914.4 KPFM of Ferroelectric Materials 44114.5 Recent Advances 445
14.5.1 Open-Loop KPFM 44514.5.2 Time-Resolved KPFM 447
14.6 Summary and Outlook 447Acknowledgments 448References 448
VOLUME II
List of Contributors xviiPreface xxiii
Introduction: Why Nanoscale Ferroelectrics and Multiferroics? xxvMiguel Alguero, J. Marty Gregg, and Liliana Mitoseriu
PART C 461
Nanoscale Effects: Bulk Properties
xii Contents
15 Nanostructured Barium Titanate Ceramics: Intrinsic versus ExtrinsicSize Effects 473Liliana Mitoseriu and Lavinia P. Curecheriu
15.1 Introduction 47315.2 Applications of BaTiO3 Ceramics; Actual Demands for Passive
Components 47615.3 Size-Dependent Phenomena in Ferroelectrics 478
15.3.1 General Properties 47815.3.2 Theoretical Description of Size-Dependent Phenomena in
Ferroelectrics 47915.4 Size-Dependent Properties in BaTiO3 Ceramics: Intrinsic versus
Extrinsic Size Effects 48615.4.1 Size-Dependent Properties of BaTiO3 Ceramics with Grain Size
in the Range of Micrometers 48615.4.2 Size-Dependent Properties of BaTiO3 Nanoceramics 487
15.5 Conclusions 501Acknowledgments 501References 501
16 The Effects of Ceramic Nanostructuring in High-SensitivityPiezoelectrics 512Harvey Amorın, Ricardo Jimenez, Jesus Ricote, Alicia Castro, andMiguel Alguero
16.1 Technological Drive for Ceramic Nanostructuring of High-SensitivityPiezoelectrics 512
16.2 State of the Art Ferroelectric Materials for Piezoelectric Technologies 51416.2.1 Commercial, PZT-Based Hard and Soft Piezoceramics 51416.2.2 Novel High-Sensitivity Piezoelectrics 516
16.3 Nanostructuring Effects in Perovskite Systems with PZT-like MPBs 51916.3.1 Basic Phenomenology 51916.3.2 Grain Size Dependence of Room Temperature Properties 52516.3.3 Grain Size Against Boundary Effects 533
16.4 Nanostructuring Effects in Perovskite Systems with Intrinsic ChemicalInhomogeneity 540
16.5 Summary and Future Perspectives 545Acknowledgments 546References 547
17 Correlation between Microstructure and Electrical Properties ofFerroelectric Relaxors 554Jelena D. Bobic, Jan Macutkevic, Robertas Grigalaitis, Maksim Ivanov,Mirjana M. Vijatovic Petrovic, Juras Banys, and Biljana D. Stojanovic
17.1 Introduction 55417.2 Perovskite Relaxors 558
Contents xiii
17.2.1 Nanosized PMN Powders and Nanostructured Ceramics 55817.2.2 Nanostructured PbSc 1
2Nb 1
2O3 Ceramics 566
17.3 Aurivillius Lead-Free Ferroelectric Relaxors 57017.3.1 Relaxor BaBi4Ti4O15 Ceramic System 57217.3.2 Grain Size-Dependent Electrical Properties of BaBi4Ti4O15
Ceramics 57417.3.3 BaBi4Ti4O15 Doped Ceramics 577
17.4 Conclusions 580References 581
18 Local Field Engineering Approach for Tuning Dielectric andFerroelectric Properties in Nanostructured Ferroelectrics andComposites 588Leontin Padurariu and Liliana Mitoseriu
18.1 Introduction 58818.2 Finite Element Method 59018.3 The Role of Local Electric Field Inhomogeneity on Tunability
Properties 59318.3.1 Nanostructured Ferroelectric Ceramics 59618.3.2 Porous Ferroelectric Ceramics 59918.3.3 Composites with Non-linear Matrix and Conductive
Inclusions 60018.4 Switching Properties in Inhomogeneous Ferroelectrics 603
18.4.1 Classical Preisach Model 60318.4.2 Switching in Nanostructured Ferroelectric Ceramics 60818.4.3 Switching in Porous Ferroelectrics 609
18.5 Conclusions 610Acknowledgments 611References 611
Nanoscale Effects: Thin-Film Properties
19 Ferroelectric Phase Transitions in Epitaxial Perovskite Films 617Marina Tyunina
19.1 Introduction 61719.2 Experimental Study of Phase Transition 618
19.2.1 Bulk Ferroelectrics and Relaxors 61819.2.2 Epitaxial Thin Films 622
19.3 Dielectric Permittivity in Thin Films 62319.3.1 Thin-Film Capacitor 62319.3.2 Derivative of Inverse Permittivity 62719.3.3 Thermo-optical Behaviour 634
19.4 Phase Transitions in Epitaxial Films 63519.4.1 Pb0.5Sr0.5TiO3 63519.4.2 BaTiO3 637
xiv Contents
19.4.3 KTaO3 63819.4.4 PbSc0.5Nb0.5O3 638
19.5 Concluding Remarks 639Acknowledgments 640References 640
20 Interfaces in Epitaxial Ferroelectric Layers/Multilayers and Their Effecton the Macroscopic Electrical Properties 645Lucian Pintilie, Andra G. Boni, Cristina Chirila, Luminita M. Hrib, AlinIuga, Lucian Trupina, Ioana Pintilie, Iuliana Pasuk, Raluca Negrea, CorneliuGhica, Mihaela Botea, Nicoleta Apostol, and Cristian M. Teodorescu
20.1 Introduction 64520.2 Electrode Interfaces in Ferroelectric Capacitors 647
20.2.1 Interface Effects on the Macroscopic Properties 64720.2.2 Analysis of Free Surfaces and of Electrode Interfaces by
AFM/PFM, XPS, and TEM 66020.3 Interfaces in Complex Structures 667
20.3.1 PZT/ZnO 66720.3.2 Ferroelectric/Multiferroic Multilayers 669
20.4 Conclusions 671Acknowledgments 671References 671
21 Electric Field Control of Magnetism Based on Elastically CoupledFerromagnetic and Ferroelectric Domains 677Kevin J.A. Franke, Tuomas H.E. Lahtinen, Arianna Casiraghi, Diego LopezGonzalez, Sampo J. Hamalainen, and Sebastiaan van Dijken
21.1 Introduction 67721.2 Domain Pattern Transfer 67821.3 Elastic Coupling Between Magnetic and Ferroelectric Domain Walls 68121.4 Domain Size Scaling of Pattern Transfer 68621.5 Electric Field Control of Ferromagnetic Domains 68821.6 Electric Field Driven Magnetic Domain Wall Motion 69021.7 Summary and Outlook 693Acknowledgments 695References 695
Nanoscale Effects: Novel Phenomena and Applications
22 Ferroelectric Vortices and Related Configurations 700Sergei Prosandeev, Ivan I. Naumov, Huaxiang Fu, Laurent Bellaiche,Michael P.D. Campbell, Raymond G.P. McQuaid, Li-Wu Chang,Alina Schilling, Leo J. McGilly, Amit Kumar, and J. Marty Gregg
22.1 Insights from Simulations and Theory 70022.1.1 Introduction 70022.1.2 Methods 701
Contents xv
22.1.3 Discovery of Unusual Patterns in Ferroelectric Nanostructuresand Their Associated Order Parameters 704
22.1.4 Controlling and Switching of Single, Double, and MultipleVortex States 708
22.1.5 Other Phenomena Related to Vortices and Complex DipolarPatterns 712
22.1.6 Summary from the Simulations and Theory Perspective 71422.2 Insights from Experiments 714
22.2.1 Introduction 71422.2.2 Vortices and Topological Winding Numbers 71522.2.3 Continuous versus Sudden Dipole rotation 71822.2.4 Unique Core Singularity 71922.2.5 Summary and Conclusions from an Experimental Perspective 723
Acknowledgments 723References 723
23 Reentrant Phenomena in Relaxors 729Alexei A. Bokov and Zuo-Guang Ye
23.1 Introduction 72923.2 Reentrant Phases in Condensed Matter 73023.3 Relaxor Ferroelectrics 73623.4 Reentrant Relaxor Behavior in Ferroelectrics 741
23.4.1 Properties of Materials with Paraelectric–Ferroelectric–RelaxorSequence of States 742
23.4.2 Models and Theories 75223.5 Transverse Glassy Freezing and Canonical Relaxors 75323.6 Reentrant Dipolar Glass State in Quantum Paraelectrics Doped with
Dipolar Impurities 75723.7 Summary and Concluding Remarks 758Acknowledgments 759References 759
24 Functional Twin Boundaries: Multiferroicity in Confined Spaces 765Ekhard. K.H. Salje and Xiangdong Ding
24.1 Introduction 76524.2 Ferroelectric Twin Boundaries 766
24.2.1 Polar Twin Walls in CaTiO3 76824.2.2 Polar Twin Walls in SrTiO3 771
24.3 Conducting Twin Boundaries 77324.4 Thermal Conductivity 77524.5 Landau Theory of Coupled Order Parameters in Domain Walls 77624.6 Chiral Twin Walls 77824.7 High Wall Densities 78024.8 Summary 783Acknowledgment 784References 784
xvi Contents
25 Novel Approaches for Genuine Single-Phase Room TemperatureMagnetoelectric Multiferroics 789Lynette Keeney, Michael Schmidt, Andreas Amann, Tuhin Maity, NitinDeepak, Ahmad Faraz, Nikolay Petkov, Saibal Roy, Martyn E. Pemble, andRoger W. Whatmore
25.1 Introduction to Single-Phase Multiferroic Materials 78925.2 Aurivillius Phase Materials – Candidate Single-Phase Multiferroics? 79625.3 Magnetoelectric Coupling in Multiferroic Bi6TixFeyMnzO18 Systems at
Room Temperature 80125.3.1 Fabrication and Structural Analysis of
Bim+1Ti3(Mn/Fe)m-3O3m+1 Thin Films 80125.3.2 Ferroelectric Investigations of Bi6TixFeyMnzO18 thin films 80425.3.3 Assessment of Ferromagnetism in Bi6TixFeyMnzO18 Thin Films 80425.3.4 Room Temperature Magnetoelectric Coupling in
Bi6Ti2.8Fe1.52Mn0.68O18 Thin Films 81025.4 Confidence Level Assessment of Genuine Single-Phase Multiferroicity 810
25.4.1 Statistics of a Single Measurement 81225.4.2 The Inclusion Size Distribution Function 81325.4.3 Series of Measurements at Varying Resolutions 81325.4.4 Upper Limit on the Contribution to Remanent Magnetization 814
25.5 Potential Devices/Applications Based on Single-Phase MagnetoelectricMultiferroics 816
25.6 Summary and Conclusions 820References 821
26 Semiconducting and Photovoltaic Ferroelectrics 830Andrew R. Akbashev, Vladimir M. Fridkin, and Jonathan E. Spanier
26.1 Introduction 83026.2 Basic Principles of Photovoltaic Effect in Ferroelectrics 83126.3 Experimental Evidence of the Bulk Photovoltaic Effect in Ferroelectrics 835
26.3.1 BiFeO3 83526.3.2 Niobates 838
26.4 The Role of the Schottky Barrier and Depletion Layer 84026.5 Photovoltaic Effect Mediated by Ferroelectric Domain Walls 84026.6 Ferroelectric Solid Solutions: Chemical Tuning of Band-Gap 84326.7 Conclusions 847Acknowledgment 847References 847
Index 851
List of Contributors
Andrew R. Akbashev Drexel University, USA
Miguel Alguero Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superiorde Investigaciones Cientıficas (CSIC), Spain
Andreas Amann Tyndall National Institute, University College Cork, Ireland; and Schoolof Mathematical Sciences, University College Cork, Ireland
Harvey Amorın Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superiorde Investigaciones Cientıficas (CSIC), Spain
Nicoleta Apostol National Institute of Materials Physics, Romania
Juras Banys Faculty of Physics, Vilnius University, Lithuania
Laurent Bellaiche Physics Department, University of Arkansas, USA
Daniela C. Berger Departement of Inorganic Chemistry, Physical-Chemistry and Electro-chemistry, “Politehnica” University of Bucharest, Romania
J.D. Bobic Institute for Multidisciplinary Research, University of Belgrade, Serbia
Alexei A. Bokov Department of Chemistry and 4D LABS, Simon Fraser University,Canada
Andra G. Boni National Institute of Materials Physics, Romania
Mihaela Botea National Institute of Materials Physics, Romania
Inigo Bretos Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior deInvestigaciones Cientıficas (CSIC), Spain
Maria Teresa Buscaglia Institute of Energetics and Interphases, National ResearchCouncil, Italy
Vincenzo Buscaglia Institute of Energetics and Interphases, National Research Council,Italy
Michael P.D. Campbell School of Maths and Physics, Queen’s University Belfast, North-ern Ireland, United Kingdom
Arianna Casiraghi NanoSpin, Department of Applied Physics, Aalto University Schoolof Science, Finland
xviii List of Contributors
Alichandra Castro CICECO – Aveiro Institute of Materials, Department of Materials andCeramic Engineering, University of Aveiro, Portugal
Alicia Castro Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior deInvestigaciones Cientıficas (CSIC), Madrid, Spain
Li-Wu Chang School of Maths and Physics, Queen’s University Belfast, Northern Ireland,United Kingdom
Cristina Chirila National Institute of Materials Physics, Romania
Frank Clemens Laboratory for High Performance Ceramics, Empa, Swiss Federal Labo-ratories for Materials Science and Technology, Switzerland
Covadonga Correas Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Supe-rior de Investigaciones Cientıficas (CSIC), Spain; and College of Engineering, SwanseaUniversity, United Kingdom
Lavinia P. Curecheriu Department of Physics, “Alexandru Ioan Cuza” University,Romania
Nitin Deepak Tyndall National Institute, University College Cork, Ireland
Marco Deluca Materials Center Leoben Forschung GmbH, and Institut fur Struktur- undFunktionskeramik, Montanuniversitaet Leoben, Austria
Xiangdong Ding State Key Laboratory for Mechanical Behavior of Materials, Xi’anJiaotong University, China
Christopher De Dobbelaere Inorganic and Physical Chemistry Group, Institute for Mate-rials Research, Universiteit Hasselt and imec vzw, Division imomec, Belgium
C. Doubrovsky Laboratoire de Physique des Solides, Universite de Paris Sud, Campusd’Orsay, France
Ahmad Faraz Tyndall National Institute, University College Cork, Ireland
Liliana P. Ferreira Biosystems and Integrative Sciences Institute, Department of Physics,University of Coimbra, Portugal
Paula Ferreira CICECO – Aveiro Institute of Materials, Department of Materials andCeramic Engineering, University of Aveiro, Portugal
Pascale Foury-Leylekian Laboratoire de Physique des Solides, Universite de Paris Sud,Campus d’Orsay, France
Kevin J. A. Franke NanoSpin, Department of Applied Physics, Aalto University Schoolof Science, Finland
Vladimir M. Fridkin Drexel University, USA; and Russian Academy of Sciences,Moscow, Russian Federation
Huaxiang Fu Physics Department, University of Arkansas, USA
Andreja Gajovic Molecular Physics Laboratory, Institute Rudjer Boskovic, Croatia
List of Contributors xix
Corneliu Ghica National Institute of Materials Physics, Romania
Margarida Godinho Biosystems and Integrative Sciences Institute, Department ofPhysics, Faculty of Sciences, University of Lisbon, Portugal
Martha Greenblatt Department of Chemistry and Chemical Biology, Rutgers, The StateUniversity of New Jersey, USA
J. Marty Gregg School of Maths and Physics, Queen’s University Belfast, Northern Ire-land, United Kingdom
R. Grigalaitis Faculty of Physics, Vilnius University, Lithuania
Sampo J. Hamalainen NanoSpin, Department of Applied Physics, Aalto UniversitySchool of Science, Finland
An Hardy Inorganic and Physical Chemistry Group, Institute for Materials Research,Universiteit Hasselt and imec vzw, Division imomec, Belgium
Luminita M. Hrib National Institute of Materials Physics, Romania
Teresa Hungria Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superiorde Investigaciones Cientıficas (CSIC), Spain; and Centre de Microcaracterisation RaimondCastaing, UMS 3623, France
Alan J. Hurd Los Alamos National Laboratory, USA
Adelina-Carmen Ianculescu Department of Oxide Materials Science and Engineering,“Politehnica” University of Bucharest, Romania
Alin Iuga National Institute of Materials Physics, Romania
Maksim Ivanov Faculty of Physics, Vilnius University, Lithuania
Ricardo Jimenez Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superiorde Investigaciones Cientıficas (CSIC), Spain
Lynette Keeney Tyndall National Institute, University College Cork, Ireland
Michael R. Koblischka Institute of Experimental Physics, Saarland University, Germany
Anjela Koblischka-Veneva Institute of Experimental Physics, Saarland University,Germany
Amit Kumar School of Maths and Physics, Queen’s University Belfast, Northern Ireland,United Kingdom
Tuomas H.E. Lahtinen NanoSpin, Department of Applied Physics, Aalto UniversitySchool of Science, Finland
Diego Lopez Gonzalez NanoSpin, Department of Applied Physics, Aalto UniversitySchool of Science, Finland
M. Lourdes Calzada Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Supe-rior de Investigaciones Cientıficas (CSIC), Spain
xx List of Contributors
Axel Lubk Triebenberg Laboratory, Technische Universitat Dresden, Germany
Tony Lusiola Laboratory for High Performance Ceramics, Empa, Swiss Federal Labora-tories for Materials Science and Technology, Switzerland
Leo J. McGilly Ceramics Laboratory, Ecole Polytechnique Federale de Lausanne (EPFL),Switzerland
Raymond G.P. McQuaid School of Maths and Physics, Queen’s University Belfast, North-ern Ireland, United Kingdom
J. Macutkevic Faculty of Physics, Vilnius University, Lithuania
Cesar Magen Instituto de Nanociencia de Aragon-ARAID, Universidad de Zaragoza,Spain
Tuhin Maity Tyndall National Institute, University College Cork, Ireland
Barbara Malic Electronic Ceramics Department, Jozef Stefan Institute, Slovenia
Liliana Mitoseriu Faculty of Physics, University “Alexandru Ioan Cuza”, Romania
Evagelia G. Moshopoulou Institute of Nanoscience and Nanotechnology, National Centerfor Scientific Research “Demokritos”, Greece; and Laboratoire de Physique des Solides,Universite de Paris Sud, Campus d’Orsay, France
Ivan I. Naumov Carnegie Institution of Washington, USA
Raluca Negrea National Institute of Materials Physics, Romania
Marius Olariu Department of Electrical Measurements & Materials, Technical UniversityGh. Asachi Iasi, Romania
Leontin Padurariu University “Alexandru Ioan Cuza”, Romania
Katharine Page Spallation Neutron Source, Oak Ridge National Laboratory, USA
Iuliana Pasuk National Institute of Materials Physics, Romania
Martyn E. Pemble Tyndall National Institute, University College Cork, Ireland; andDepartment of Chemistry, University College Cork, Ireland
Nikolay Petkov Tyndall National Institute, University College Cork, Ireland
M.M. Vijatovic Petrovic Institute for Multidisciplinary Research, University of Belgrade,Serbia
Ioana Pintilie National Institute of Materials Physics, Romania
Lucian Pintilie National Institute of Materials Physics, Romania
Sergei Prosandeev Physics Department, University of Arkansas, USA and Physics Depart-ment and Research Institute of Physics, Southern Federal University, Russia
Jesus Ricote Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior deInvestigaciones Cientıficas (CSIC), Spain
List of Contributors xxi
Brian J. Rodriguez Conway Institute of Biomolecular and Biomedical Research, Univer-sity College Dublin, Ireland
Saibal Roy Tyndall National Institute, University College Cork, Ireland
Ekhard. K.H. Salje Department of Earth Sciences, University of Cambridge, UnitedKingdom
Alina Schilling School of Maths and Physics, Queen’s University Belfast, Northern Ireland,United Kingdom
Michael Schmidt Tyndall National Institute, University College Cork, Ireland
Theodor Schneller Institut fur Werkstoffe der Elektrotechnik II, RWTH Aachen Univer-sity, Germany
Stella Skiadopoulou CICECO – Aveiro Institute of Materials, Department of Materialsand Ceramic Engineering, University of Aveiro, Portugal
Etienne Snoeck Centre d’Elaboration de Materiaux et d’Etudes Structurales, CNRS,France
Jonathan E. Spanier Drexel University, USA
Biljana D. Stojanovic Institute for Multidisciplinary Research, University of Belgrade,Serbia
Bosiljka Tadic Department of Theoretical Physics, Jozef Stefan Institute, Slovenia
Cristian M. Teodorescu National Institute of Materials Physics, Romania
Gregor Trefalt Electronic Ceramics Department, Jozef Stefan Institute and Center ofExcellence NAMASTE, Slovenia; and University of Geneva, Switzerland
Lucian Trupina National Institute of Materials Physics, Romania
Roxana Trusca S.C. METAV – Research and Development, Romania
Marina Tyunina Microelectronics and Materials Physics Laboratories, University of Oulu,Finland
Marlies K. Van Bael Inorganic and Physical Chemistry Group, Institute for MaterialsResearch, Universiteit Hasselt and imec vzw, Division imomec, Belgium
Sebastiaan van Dijken NanoSpin, Department of Applied Physics, Aalto UniversitySchool of Science, Finland
Bogdan S. Vasile Department of Oxide Materials Science and Engineering, “Politehnica”University of Bucharest, Romania
Catalina A. Vasilescu Department of Oxide Materials Science and Engineering,“Politehnica” University of Bucharest, Romania
Paula M. Vilarinho CICECO – Aveiro Institute of Materials, Department of Materials andCeramic Engineering, University of Aveiro, Portugal
xxii List of Contributors
Roger W. Whatmore Tyndall National Institute, University College Cork, Ireland; Depart-ment of Chemistry, University College Cork, Ireland and Department of Materials, RoyalSchool of Mines, Imperial College London, United Kingdom
Zuo-Guang Ye Department of Chemistry and 4D LABS, Simon Fraser University, Canada
Preface
Multiferroics have been at the cutting edge of research and development in materials forICTs for over a decade. During this period steady improvements in fundamental knowl-edge have been made. At the same time, nanoscale phenomena have assumed an increasingimportance. Progress has benefited from the strong synergies with activities in nanoscaleferroelectrics, which are at a more mature stage. Multifunctionality and nanoscaling arewidely acknowledged at present as the keys to the miniaturization of solid-state electronics,and specifically nanoferronics, which is emerging as a new area with large technologicalpotential. The topic has now reached a maturity level that allows, and actually requires,books that provide a comprehensive revision of the topic, and an in-depth analysis of futuretrends. These are the objectives of Nanoscale Ferroelectrics and Multiferroics: Key Pro-cessing and Characterization Issues, and Nanoscale Effects.
It is intended to provide the increasing number of scientists and engineers, who areapproaching the topic from a range of backgrounds, with a reference/guide text that shouldhelp them to roadmap their R&D activities. The volume reviews the key issues in processingand characterization of nanoscale ferroelectrics and multiferroics, and provides a compre-hensive description of their properties. An emphasis is put on differentiating size effectsof extrinsic ones like boundary or interface effects. Nanoscale novel, recently described,phenomena that are bound to be behind major advancement in the field during the comingyears are also addressed.
The book is devised to stress, and take full advantage of, the synergies between nanoscaleferroelectrics and multiferroics. It covers materials nanostructured at all levels, fromceramic technologies like ferroelectric nanopowders, bulk nanostructured ceramics andthick films, and magnetoelectric nanocomposites, to thin films, either polycrystalline layerheterostructures or epitaxial systems, and to nanoscale free-standing objects with specificgeometries, such as nanowires and tubes at different levels of development, but all tech-nologically relevant. Nanostructuring is a requirement of the current tendency to minia-turization of ceramic technologies for microelectronics that imposes stringent conditionson processing, and has a deep impact on functional properties. Also, nanostructuring ulti-mately results in the ever-decreasing processing temperatures of thin films, a key issue tothe integration of these multifunctional oxides with silicon devices and flexoelectronics.Last but not least, a range of novel physical phenomena has been described in nanoscaleferroelectrics and multiferroics that have the potential to enable a range of disruptive tech-nologies, like magnetoelectric memory. Overall, the book reviews the current state of theart of these materials, stressing a range of specific topics at the cutting edge of research.
This project springs from the high-level European scientific knowledge platform builtwithin the COST Action Single and Multiphase Ferroics and Multiferroics with Restricted
xxiv Preface
Geometries (SIMUFER, ref. MP0904), active between March 2010 and May 2014. COST(European Cooperation in Science and Technology) is a pan-European networking instru-ment that allows researchers from COST member countries and cooperating states to jointlydevelop their ideas and initiatives in a field or topic of common interest. SIMUFER estab-lished a multidisciplinary scientific network of groups from 24 European countries and7 non-COST countries, experienced in synthesis, advanced characterization, and model-ing of all nanoscale ferroics, single-phase multiferroics, and ferroic-based combinations ofdissimilar materials. This book project arises primarily from their expertise, though it hasbeen open to world renowned experts when necessary. Chapter contributors have been care-fully selected and have all made major contributions to knowledge of the respective topics;overall, they are among the most respected scientists in the field.
IntroductionWhy Nanoscale Ferroelectrics
and Multiferroics?
Miguel Alguero1, J. Marty Gregg2, and Liliana Mitoseriu3
1Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de InvestigacionesCientıficas (CSIC), Spain
2School of Maths and Physics, Queen’s University Belfast, Northern Ireland, United Kingdom3Faculty of Physics, University “Alexandru Ioan Cuza”, Romania
I.1 Ferroics and Multiferroics
Single-phase ferroics are compounds that present one of the three (currently expandedto four) ferroic properties: ferroelectricity, ferromagnetism, or ferroelasticity, to whichferrotoroidicity has recently been added. The common feature of the four types of ferroicsis the appearance of the ferroic order; either it is a spontaneous electrical polarization,magnetization, strain, or toroidal moment, in a phase transition from a high-temperatureprototype phase to the low-temperature ferroic phase, related by a group/subgrouprelationship. This transition is always accompanied by a decrease in symmetry and thesplitting of the ferroic phase into domains (regions with a different orientation of theorder parameter). A second feature, the direct consequence of the switchable nature ofthe order parameter and of the domain dynamics, is the characteristic ferroic hysteresisloop; that is, a distinctive hysteretic dependence of the order parameter on its conjugatedfield (electric or magnetic field, mechanical stress or toroidal source vector, respectively),with two remnant states of opposite sign [1]. The four phenomena are schematicallyshown in Figure I.1. Ferroics are highly topical, advanced functional materials that havenot only enabled a range of mature and ubiquitous related technologies (like magnetic
Nanoscale Ferroelectrics and Multiferroics: Key Processing and Characterization Issues, and Nanoscale Effects,First Edition. Edited by Miguel Alguero, J. Marty Gregg, and Liliana Mitoseriu.© 2016 John Wiley & Sons, Ltd. Published 2016 by John Wiley & Sons, Ltd.
xxvi Introduction
Figure I.1 Schematics of domains and hysteretic switching for the four ferroic phenomena.Adapted by permission of IOP Publishing from [1]. © IOP Publishing. All rights reserved.
or ferroelectric information recording, ceramic ultrasound transducers, or shape memoryalloys, to name only a few examples) but are also under extensive research for a numberof novel, potentially disruptive, applications [2].
There are also compounds that simultaneously present two (or more) ferroic phenomena,known as multiferroics, among which those showing coexistence of ferroelectricity andferromagnetism (initially termed ferroelectromagnets) are receiving increasing attention[3,4]. This is not only because of their inherent multifunctionality but also for the fact thatthey are liable to show magnetoelectric coupling, and have thus the potential to enable theelectrical control of magnetism (and the magnetic control of polarization) [5].
This book specifically deals with ferroelectrics and ferroelectromagnets (either robustferromagnetic materials or canted antiferromagnets showing weak ferromagnetism), thoughthe general term multiferroics will be used following the current tendency to name
Introduction xxvii
ferroelectric–ferromagnetic materials, and in general any type of magnetic ordering com-pounds, in this way.
The choice of addressing them together only acknowledges the deep-rooted relationshipbetween the two sets of materials; multiferroism requires ferroelectricity and thus multi-ferroics have to be electrically insulating to be functional (an issue not always acknowl-edged). This feature is not easily found in magnetic materials, most of them being metallicor narrow-band gap semiconductors. Indeed, chemical bonding requirements suggest thetwo ferroic phenomena to be incompatible [6]; transition metal or rare earth atomic specieswith partially filled outer d or f electronic shells (and unpaired electrons) are necessary formagnetism, while model ferroelectric perovskite oxides are characterized by covalentlybonded transition metals (to oxygen) with empty d orbitals [7]. Nevertheless, an ever-increasing number of multiferroic single-phase materials have been reported over the lastdecade, exploring alternative mechanisms of ferroelectricity.
I.2 Ferroelectric Materials and Related Technologies
Ferroelectrics are thus materials that present a spontaneous electrical polarization, whosedirection can be reversed with an electric field (by nucleation and growth of inversiondomains, resulting in the distinctive ferroelectric hysteresis). The ferroic phase appears ata ferroelectric transition, driven by electrical polarization [8], which can be either of a dis-placive type, the most common one, associated with a crystal structure instability inducedby condensation of a transverse optical phonon (the soft mode) [9], or of an order–disordertype. Its macroscopic phenomenological description according to Landau’s theory of phasetransitions can be found in Chapter 19.
All ferroelectrics are also pyroelectric and piezoelectric, as well as electrooptic, whichturns them into a prototype of multifunctionality (even before magnetic order is added).Moreover, they are the only materials that can present these properties, intrinsically linkedto the crystal structure, in polycrystalline form (thanks to the ability to reorient the polar-ization under an electric field).
Though ferroelectricity was first described for hydrogen-bonded compounds (Rochellesalt being the first one in 1921), and there are also examples among tellurides, fluorides,and iodides [10], a number of electroactive polymers like poly(vinylidene fluoride) [11],and recent reports of ferroelectric metal organic frameworks [12], clearly oxides stand outas the ones that have enabled a range of successful ferroelectric technologies.
I.2.1 Ferroelectric Bulk Technologies
Perhaps the best-known ferroelectric, and also the first oxide shown to be so in 1944, isBaTiO3 with a perovskite structure. This model compound presents the ferroelectric transi-tion at ∼393 K and a succession of low-temperature polymorphic phase transitions betweenferroelectric phases with decreasing symmetry, from tetragonal to orthorhombic and torhombohedral, for which the polar axis (and thus the direction of the spontaneous polariza-tion defined by the displacement of the Ti4+ cation from the centre of the oxygen octahedra)changes. Polymorphism is a quite common phenomenon in ferroelectric perovskite oxidesand plays a very important role in their functionality. BaTiO3 is also the base composition
xxviii Introduction
of multilayer ceramic capacitors (after the chemical tailoring of the ferroelectric transitiondown to room temperature), one of the two large-scale, mature bulk ceramic ferroelectrictechnologies. This material and its modifications are extensively addressed in this book (seeChapters 1, 11, 12, 15, and 18), for the miniaturization of these capacitors is a case study ofthe current trends in microelectronics that require the nanostructuring of the ceramic lay-ers. In the last few years, nanostructured BaTiO3 and its solid solutions have become themain candidates for active materials used in capacitive building blocks for energy storageapplications.
The second successful technology is piezoelectric ceramics for electromechanical trans-duction. The state of the art material for these applications, which range from sensorsand actuators (like accelerometers or positioning systems for scanning probe microscopy,respectively) and their combination in smart systems (to implement active vibration damp-ing), to ultrasound generation and sensing (for medical imaging or non-destructive test-ing), and to submarine acoustics, is Pb(Zr,Ti)O3, which also has a perovskite structure.This is an oxide solid solution, for which the best properties are found at a morphotropicphase boundary (MPB) between rhombohedral and tetragonal ferroelectric polymorphs, forwhich a monoclinic phase has been recently described [13]. This material can be regarded asa modification of PbTiO3, a second model ferroelectric oxide that also shows a successionof polymorphic phase transitions, yet induced by hydrostatic pressure instead of temper-ature [14], which has been placed at one of these ferroelectric instabilities (the MPB) bybuilding up chemical pressure (achieved by substitution of Zr4+ for Ti4+). As a matter offact, the very good electromechanical response of this material is a combination of twoeffects, a crystal contribution, associated with the existence of a transverse lattice insta-bility at the monoclinic tetragonal boundary [15], and an extrinsic contribution, associatedwith the fact that ferroelectric perovskite oxides are also ferroelastic (and therefore multi-ferroic, but not ferroelectromagnets). The spontaneous strain develops at the ferroelectrictransition along with the polarization (the two parameters are intrinsically coupled), and asa consequence ferrroelectric–ferroelastic domains appear (in addition to polarization inver-sion domains).The non-180◦ (90◦ in the tetragonal case) domain walls are mobile understress and electric field (unlike 180◦ walls that only move under an electric field), givingway to a wall contribution to the piezoelectric effect [16]. Moreover, the domain dynamics isenhanced at the morphotropic phase boundary. In addition, chemical (or doping) engineer-ing of Pb(Zr,Ti)O3 has been developed that enables a range of soft and hard piezoelectricceramics with tailored properties for specific applications. Piezoelectric ceramics are alsobeing considered for novel applications, such as energy harvesting [17] and magnetoelec-tric composites (see later). Further explanations of the mechanisms, along with a review ofalternative materials, can be found in Chapter 16. This technology is not oblivious to thegeneral miniaturization trend and nanostructuring can also be anticipated.
Other examples of ferroelectric ceramic bulk technologies are infrared (IR) cameras fornight vision (and, in general, IR detectors for a range of applications exploiting the pyro-electric effect) and electrooptic devices. Modifications of PbTiO3 like (Pb,La)TiO3 andtransparent (Pb,La)(Zr,Ti)O3 are usually the material choices, respectively. An excellentreview of ferroelectric ceramics and related technologies can be found in [18].
Also successful ferroelectric single-crystal technologies are presently available. The bestexamples are surface acoustic wave (SAW) devices for radio frequency and microwavesignal conditioning, based on ferroelectric LiNbO3 substrates. At the very end of the