introduction to the difraction analysis and sans method
DESCRIPTION
Students: Dana-Maria GHITA (Univ. of Craiova, Romania) Nicoleta-Madalina GIURGEA (Univ. of Bucharest, Romania) Andreea OPREA (Univ. of Bucharest, Romania) Claudia-Teodora TEODORESCU-SOARE (Univ. of Jassy, Romania) Project Coordinators: Dr. M . L . CRAUS (FLNP) Dr. A . I. KUKLIN (FLNP). - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/1.jpg)
Introduction to the difraction analysis and
SANS methodStudents:
Dana-Maria GHITA (Univ. of Craiova, Romania) Nicoleta-Madalina GIURGEA (Univ. of Bucharest, Romania) Andreea OPREA (Univ. of Bucharest, Romania) Claudia-Teodora TEODORESCU-SOARE (Univ. of Jassy, Romania)
Project Coordinators:
Dr. M. L. CRAUS (FLNP) Dr. A. I. KUKLIN (FLNP)
JINR Summer Student Practice 5-25 July 2010
![Page 2: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/2.jpg)
Part 1:Corelations between
structure and transport caracteristics
of manganites with Cr impurities (La0.54Ho0.11Sr0.35)
(Mn1-xCrx)O3
![Page 3: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/3.jpg)
Outline
Work done within the Project Overview Results Conclusions
![Page 4: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/4.jpg)
Work Done Within the Project
Manganite samples with the general structure La0.54Ho0.11Sr0.35Mn1-xCrxO3 have been studied using FullProf Suite code for existing data at (x = 0.05; 0.10; 0.15; 0.20).
The goal of investigation was to estimate qualitatively :
(1) the variation of the lattice constant values in terms of Cr impurity concentration
(2) microstrain and crystallite average size dependence on the Cr concentration.
![Page 5: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/5.jpg)
Outline
Work done within the Project
Overview Results Conclusions
![Page 6: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/6.jpg)
Overview
The samples: La0.54Ho0.11Sr0.35Mn1-xCrxO3 manganites were prepared by sol-gel
method using oxides and acetates and sintered in air at 1200
C for 15 h.
It is known:The samples show perovskite phases, with orthorhombic
structure (Space Group – P n m a). ABO3 perovskito-manganites determine the charge transport behavior and complex magnetic and crystalline structures.
X-ray data for samples (with different Cr concentrations) mentioned in our report was obtained with Hubber-Guinier diffractometer by using Cr Kα1 radiation and was handled using FullProf Suite code.
![Page 7: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/7.jpg)
Unit cell of manganite La0.54Ho0.11Sr0.35Mn1-xCrxO3
Features:
- Distorted Perovskite
- Orthorhombic space group: Pnma #62
- Primitive lattice (P)
- Glide plane (n) perpendicular to a axis
- Mirror plane (m) perpendicular to b axis
- Glide plane (a) perpendicular to c axis
![Page 8: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/8.jpg)
FullProf Main Features The program has been mainly developed for Rietveld analysis
(structure profile refinement) of neutron (nuclear and magnetic scattering) or X-ray powder diffraction data collected at constant or variable step in scattering angle 2θ
• X-ray diffraction data: laboratory and synchrotron sources.
• Neutron diffraction data: Constant Wavelength (CW) and Time of Flight (TOF).
• The scattering variable may be 2θ in degrees, TOF in microseconds and Energy in KeV.
• Background: fixed, refinable, adaptable, or with Fourier filtering.
• Choice of peak shape for each phase: Gaussian, Lorentzian, modified Lorentzians, pseudo-Voigt, Pearson-VII, Thompson-Cox-Hastings (TCH) pseudo-Voigt, numerical, split pseudo-Voigt, convolution of a double exponential with a TCH pseudo-Voigt for TOF.
• Multi-phase (up to 16 phases).
• Absorption correction for a different geometries. Micro-absorption correction for Bragg-Brentano set-up.
free program http://www.ill.eu/sites/fullprof/
![Page 9: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/9.jpg)
FullProf Main Features • Choice between automatic generation of hkl and/or symmetry operators
and file given by user.
• Magnetic structure refinement (crystallographic and spherical representation of the magnetic moments).
• hkl-dependence of the position shifts of Bragg reflections for special kind of defects.
• Profile Matching. The full profile can be adjusted without prior knowledge of the structure (needs only good starting cell and profile parameters).
• Quantitative analysis without need of structure factor calculations.
• Chemical (distances and angles) and magnetic (magnetic moments) slack constraints. They can be generated automatically by the program.
• The instrumental resolution function (Voigt function) may be supplied in a file. A microstructural analysis is then performed.
• Neutron (or X-rays) powder patterns can be mixed with integrated intensities of X-rays (or neutron) from single crystal or powder data.
• Full Multi-pattern capabilities. The user may mix several powder diffraction patterns (eventually heterogeneous: X-rays, TOF neutrons, etc.) with total control of the weighting scheme.
![Page 10: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/10.jpg)
Outline
Work done within the Project Overview
Results Conclusions
![Page 11: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/11.jpg)
Observed and calculated difractograms of
La0.54Ho0.11Sr0.35Mn0.95Cr0.05O3 (FullProf method)
![Page 12: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/12.jpg)
Observed and calculated difractograms of
La0.54Ho0.11Sr0.35Mn0.90Cr0.10O3 (FullProf method)
![Page 13: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/13.jpg)
Observed and calculated difractograms of
La0.54Ho0.11Sr0.35Mn0.85Cr0.15O3 (FullProf method)
![Page 14: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/14.jpg)
Observed and calculated difractograms of
La0.54Ho0.11Sr0.35Mn0.80Cr0.20O3 (FullProf method)
![Page 15: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/15.jpg)
Variation of the lattice constants and the unit cell volume (a,b,c,V) vs. Cr
concentration x
x a(Å) b(Å) c(Å) V(Å3)
0.05 5.4229 7.6628 5.4038 224.553
0.10 5.3786 7.5831 5.3924 219.937
0.15 5.3793 7.5922 5.3865 219.989
0.20 5.3767 7.5946 5.3823 219.780
![Page 16: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/16.jpg)
Variation of the microstrain Ɛ and of the apparent size of the crystallite vs. Cr
concentration x
x Ɛ D (Å)
0.05 0.0289579 467.86
0.10 0.0317542 423.55
0.15 0.0265669 712.69
0.20 0.0222624 601.97
![Page 17: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/17.jpg)
Outline
Work done within the Project Overview Results
Conclusions
![Page 18: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/18.jpg)
Conclusions to Part 1
Lattice constants a and c decrease decrease monotonicallymonotonically, while b and unit cell volume V vary non-monotonicallyvary non-monotonically with the Cr (chrome) concentration.
The microstrain shows a maximummaximum, while the average size of crystallites shows non-monotonicnon-monotonic variation with Cr concentration .
![Page 19: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/19.jpg)
Part 2 : SANS - Introduction•Small angle neuton scattering is a method of analisys used in research for the determination of the structures and parameters of different solid samples.
•The measured magnitude in a small angle scattering experiment is the intensity as a function of the momentum transfer Q=4π/λ sinΘ (scattering vector).
• SANS techniques:
-The pin-hole SANS covers the conventional range of 1 to 100nm. This range is exptended by the focusing SANS with either mirrors or lenses up to 1000nm.
-The double crystal (Bonse Hart) diffractometer reaches length scales in the μm range.
![Page 20: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/20.jpg)
Information which can be obtained by SANS
• Sizes, spatial correlations and shapes of particles, aglomerates, pores and fractals in crystalline and amorphous states, as well as in solutions on a length scale ranging from 1 nm up to several hundred nanometers
• Phase transitions
• Degree of polydispersity
• Aggregation numbers
• Molecular weight
• Geometric peculiarities
![Page 21: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/21.jpg)
Special methods
Contrast Variation Method– Determination of object density – Investigation of system homogeneity
Label Method– Analysis of density distribution inside the object under study
![Page 22: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/22.jpg)
1 – two reflectors;2 – zone of reactor with
moderator;3 – chopper;
4 – first collimator;5 – vacuum tube;
6 – second collimator;7 – thermostate;
8 – samples table;9 – Vn-standard;
10 – ring-wire detector; 11 – position-sensitive
detector "Volga";12 – direct beam
detector.
YUMO-Frank Laboratory of Neutron Physics, Joint Institute of Nuclear Physics, Dubna, Russia
![Page 23: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/23.jpg)
SAXS and SANS comparison
Commons: - elastic
- coherent
- magnetic scattering
- nuclear
Differences : SAXS - big scattering angle
- q range = 0.8 ÷1 Å-1
SANS - small scattering angle
- q range= 0.001 ÷1 Å-1
![Page 24: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/24.jpg)
Conclusions to Part 2
• SANS is a powerful method for the investigation of sizes, shapes and density of particles in the range of: 20 ÷ 10 000Å.
• The neutron measurements also enable the determination of magnetic correlations inside samples.
• Contrast variation methods in the SANS framework allow nuclear and magnetic density estimates.
• Etc.
![Page 25: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/25.jpg)
References• “Transport phenomena in La0.54Ho0.11Sr0.35Mn1-xCuxO3
manganites” Mihail-Liviu Craus1,2, Nicoleta Cornei 3, Ahmed Islamov2 and Vasyl M. Garamus4
• http://www.ill.eu/sites/fullprof/
• www.flnr.jinr.ru
• Neutron Scattering, Thomas Brϋckel, Gernot Heger, Dieter Richter and Reiner Zorn, RWTH Aachen, University of Mϋnster
• Perovskiti Magnetorezistivi: sinteza, proprietati si aplicatii, Mihail-Liviu Craus, Nicoleta Cornei, Mihai Lozovan, Viorel Dobrea, Iassy:Alfa, 2008
• An introduction to the program FullProf, Juan Rodríguez-Carvajal, Laboratoire Léon Brillouin (CEA-CNRS), CEA/Saclay, 91191 Gif sur Yvette Cedex, FRANCE
![Page 26: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/26.jpg)
Acknowledgments
• We are indebted to the Project leaders for their guidance &
patience.
• Thanks to the Direction and staff of UC for the nice
organization of the summer student practice
• Thanks to Prof. Dr. Gh. ADAM and Dr. S. ADAM for advice
during the Summer practice
• Thanks to Dr. O. CULICOV for the Reactor tour
• Also thanks to Phd. Student R. ERHAN for good advices during
the Summer practice
![Page 27: Introduction to the difraction analysis and SANS method](https://reader035.vdocument.in/reader035/viewer/2022081519/5681464a550346895db35c56/html5/thumbnails/27.jpg)
Thank You for Attention!!
Thank you for attention!!