iron-based and mgb2 classes of superconductors
TRANSCRIPT
3rd-14th September 2018 EASIschool in Vienna
UNIVERSITÀ DEGLI STUDI DI GENOVA
Marie Sklodowska-Curie Action (MSCA) Innovative Training Networks (ITN)H2020 FP grant agreement no. 764879
Iron-based and MgB2 classes of superconductors
Part II - IBS
The lecture will review:1) the basic properties of IBS , including the
interplay between superconductivity and AFM, unconventional pairing;
2) the superconducting properties, including the upper critical field Hc2 , critical current density Jc and critical parameters;
3) the development and fabrication of wiresand tapes.
2014
100 KFeSe
Single layer
58 K
112 type (CaFeAs2)
Intercalated FeSe-11122 ( KFe2Se2)
REFeAsO1111
Tc,max = 58 K
AEFe2As2122
Tc,max = 40 K
Fe(Se,Te)11
Tc,max = 21 K
Superconductivity occurs uponsubstituting O with F, HDeficency of O heterovalent REFe with Coheterovalent AE metalexternal pressureinternal pressuresubstitution of Te with Se, Sexternal pressure
M1-xAExFe2-yTMyAs2-zPz
RE=La, Ce, Pr 40 -46
Tc is higher in the order 1111 > 122 > 11. Does interlayer spacing of FeAs layers enhance optimal Tc ?
anionheightFe
Pn, Ch
Phenomenological correlationof Tc with the tethraedron angle and with the anion hight
Anion hight is a structural parameter associated with strength of spin fluctuation
H.Hosono, et al., Mater. Today 21 (2018) 278.
RE
OF
AsFe
LaFeAsO1-xFx
LaFeAsO1-xFx
S. Sanna et al., PRB 80, 052503 (2009).A. Martinelli et al PRL 106, 227001 (2011)
SmFeAsO1-xFx
FeTe
FeSe
0 50 100 150 200 2500
2
4
6
resis
tivity
[mΩ
cm
]
Temperature [K]
LaFeAsOC. de la Cruz et al., 2008 Nature 453 899
a SDW ordering of Fe (≈0.4µB/Fe ) associated to a tetragonal-orthorhombic transition
0 50 100 150 200 250 3000.0
0.5
1.0
1.5
ρ (m
Ω c
m)
T (K)
FeTe
FeTe exhibits:bicollinear AFM ordering of Fe (≈2.5 µB/Fe ) spin direction 45° rotated in
respect to 1111 and 122Tetragonal to monoclinic transition
11 1111-
Igor I. Mazin, Nature 464 (2011) 183D. J. Singh and M.-H. Du: Phys. Rev. Lett. 100 (2008)
Superconducting order parameter: MgB2 : two-band s wave with the same sign IBS : two-band s± wave
MgB2 IBS
Q
holes
electrons
0.1 1 100.0
0.2
0.4
0.6
0.8
1.0
V3Si
MgB2
Nd-1111
T c/Tc0
g=Γ/2πkBTc0
YBCO
C Tarantini et al.,PRL 104, 087002 (2010)
S Onari eta l., PRL 103, 177001 (2009)]
In case of s ± wave pairing a rapidsuppression of Tc with impuritieshas been predicted
Superconductivity in IBS isquite robust agains disorder
I. Pallecchi et al., SUST 31, 034007 (2018)
0.0 0.5 1.0 1.5
0.4
0.6
0.8
1.0
T c/Tc0
g
1111
122
The lecture will review:1) the basic properties of IBS , including the
interplay between superconductivity and AFM, and unconventional pairing;
2) the superconducting properties, including the upper critical field Hc2 , the critical current density Jc and the critical parameters;
3) the development and fabrication of wires and tapes.
Putti et al. SUST 23 034003 (2010)
Slope -15 T/K Anisotropy is 5
30 35 40 45 500
10
20
30
40
50
60 H//ab H//c
µ 0H
c2 [T
]
T [K]
NdFeAs(OF)
8 12 16 20
T [K]
Ba(FeCo)2As2
Slope -4.9 T/K Anisotropy is 2-1.5
0 5 10 15 20
T [ K ]
Fe(TeSe)
Slope -50 T/K Anisotropy 3-1
1111 11
C. Tarantini et al., PRB 84, 184522 (2011)
11
1111
1111 122 11 YBCO MgB2
Tc [K] 55 38 16 93 39
Bc2 (0) [T] >50 60 55 >50 20-30
ξab [nm] 2.5 3 1.5 2.2 10
γΗ 5 2 2-3 4-14 3-5
λab (nm) 200 200 490 180 50-100
Ginzburg number Gi
4·10-4 2·10-5 1·10-3 >10-3 <10-5
pairing Not BCS Not BCS Not BCS Not BCS BCS
Several similarities with HTS : High Hc2, small coherence length, unconventional pairingbut, lower anisotropy
𝐺𝐺𝑖𝑖 = ~ ∆𝑇𝑇𝑇𝑇𝑐𝑐
Width of the critical regime around Tc
H.Sato, et al., APL 104, 182603 (2014)
Jc @ low temperature is:
Large (above 106 A/cm2 in
self-field)
Almost field independent
@ 5 K
Jc @ low temperature is:
Large (above 106 A/cm2 in
self-field)
Almost field independent
Nearly isotropic
Field independentCritical current density:
Jc is almost isotropic with increasing
both the temperature and the
magnetic field.
Jc remains above 105 A/cm2 @0.8 Tc
Pinning by point defects
P. Yuan et al., SUST 29 (2016) 035013
Tc= 18 K
Kurth et al., EUCAS 2015Iida , Sci. Rep. 3:2139 (2013)Tarantini et al., Sci. Rep. 4, (2014).Sato et al., Applied Physics Letters 104, 182603 (2014)Si, W. et al. Nat. Commun. 4:1347 (2013).
0 10 20 30 40 501
10
100
1000
F p , G
N/m
3
B , Tesla
Nd-1111 (Kurth et al.) Sm-1111 (Iida et al.) 122 (Tarantini et al.) 11 (Si et al.)
YBCO 2G H//c
NbSn3
Filled symbols: H//abEmpty symbols: H//c
400 GN/m3
0 5 10 15 20 25 30 35 40 45 5010-3
10-2
10-1
100
our data W. Si et al., APL 106 2015
J cGB/J
cG
misorientation angle
Also in IBS Jc is suppressed by misaglinedgrains
In HTS 𝜽𝜽𝑪𝑪~𝟒𝟒° In IBS 𝜽𝜽𝑪𝑪~𝟏𝟏𝟏𝟏𝟏 IBS has Advantageous GBs over HTS
0 10 20 30 40
104
105
106
107
J GB (
A/cm
2 )
Θ (°)
YBCO
0 10 20 30 40
104
105
106
107
11 (Si et al. 2015)11 (Kawale et al. 2014)
Co doped 122 (Lee et al. 2009)
P doped 122 (Ikuta et al. 2013)
J GB [A
/cm
2 ]
θ [deg]
Co doped 122 (Katase et al.2011)YBCO
Kawale et al.,ASC 2014Si et al, Appl. Phys. Lett. 106 032602 (2015)11 bicrystals
122 bicrystalsLee et al., Appl. Phys. Lett. 95, 212505 (2009).Katase et al., Nat. Commun. 2, 409 (2011)Sagakami et al.,Physica C 494 (2013) 181–184
11 bicrystals
122 bicrystals
The lecture will review:1) the basic properties of IBS , including the interplay
between superconductivity and AFM, unconventional pairing;
2) the superconducting properties, including the upper critical field Hc2 , the critical current density Jc and the critical parameters;
3) the development and fabrication of wires and tapes.
DyBa2Cu3O7-y polycrystal SmFeAsO0.85 polycrystal
Seuntjens et al., JAP. 67, 2007 (1990) Yamamoto et al., SUST 21, 095008 (2008)
4.2 K
Intragrain Jc Jc Intragrain Jc
H.Hosono, et al., Mater. Today 21 (2018) 278.
Best performaces for the 122 family
Jc rather flat and in the best samples close to 105 A/cm2
above 10 T
Main technologies for ReBCO-CC manufacturing
The goal: to achieve highly in-plane oriented practical metal-tape substrates.
Si W. et al, Nat. Comm 4 (2013) 1347
Si W. et al, APL98 (2011) 262509
Excellent results obtained on 11 thin
films growth on IBAD and RABiTS
Jc>𝟏𝟏𝟏𝟏𝟓𝟓𝑨𝑨/𝒄𝒄𝒄𝒄𝟐𝟐 @ 35 T on RABiTS
Jc>𝟏𝟏𝟏𝟏𝟓𝟓𝑨𝑨/𝒄𝒄𝒄𝒄𝟐𝟐 @ 9 T on IBAD-LMO
with in-plane misaglinment ∆𝝓𝝓 ∼7.7°
Xu Z. et al., SUST 30 (2017) 035003
IBAD-LMO
K. Iida et al., Sci. Rep. 7 (2017) 39951.
IBAD-MgO
H. Sato et al., Sci. Rep. 6 (2016) 36828
2010 2012 2014 2016 2018101
102
103
104
105
106
J c [
A/cm
2 ]
Year
PIT CC 1111PIT CC 122PIT CC 11
T= 4.2Kself-field
I. Pallecchi, M. Eisterer, A. Malagoli, M. Putti, SUST (2015) 28
Coated Conductors
PIT Wires& Tapes
2010 2012 2014 2016 2018100
101
102
103
104
105
106
J c (A/
cm2 )
Year
1111 122 11@ B= 10 T
Practicalapplication
Jc anisotropyAwaji EUCAS2015
Courtesy: Y.Ma CAS
Effect of strain
H.Hosono, et al., Mater. Today 21 (2018) 278.
Cross-section of 114 multi filamentary 122 wires&tapes
The first 100-m-class 122 wire
H.Hosono, et al., Mater. Today 21 (2018) 278.
Qingjin XU” Status of high field magnet technology for CEPC-SPPC” 2017 FCC Week 29 May-2 June 2017 Berlin, Germany
Advantages
High field superconductors
Isotropic Jc
Effective pinning mechanisms
Suitable for fabrication with
cheap method
DisadvantagesModerate Tc
Hazardous material
Technology too young
H.Hosono, et al., Mater. Today 21 (2018) 278.