Carmine SENATORE

Superconductivity and its applications

Lecture 9

http://supra.unige.ch

Group of Applied SuperconductivityDepartment of Quantum Matter Physics

University of Geneva, Switzerland

Bi2212 Bi2223

a [Å] 5.415 5.413

b [Å] 5.421 5.421

c [Å] 30.880 37.010

# of adjacent CuO2 planes

2 3

Tc [K] 91 110Bi2212

Bi2Sr2CaCu2O8+x

Bi2223Bi2Sr2Ca2Cu3O10+x

3 CuO2 planes 2 CuO2 planes

O

Ca

Cu

Sr

Bi

Previously, in lecture 8 - HTS materials for applications

Previously, in lecture 8HTS materials for applications

Copper oxides with highly anisotropic structures, texturing (grain orientation) is required in technical superconductors

Produced by Powder-In-Tube methodAg matrix materialTape geometry to achieve c-axis texturingIc depends on the magnetic field orientation

Produced by Powder-In-Tube methodAg matrix materialRound wire, spontaneous radial texturing of the c-axisIsotropic properties of Ic

Tc [K] texture

Bi2223 110 c-axis

Bi2212 91c-axis

(radial)

Bi2223 route

Bi2212 route

Bi2212 conductors are multifilamentary round wires

Previously, in lecture 8

Bi2212 & Bi 2223 conductor technology

Bi2223 conductors are multifilamentary tapes

Bi2212 Bi2223 Y123

a [Å] 5.415 5.413 3.8227

b [Å] 5.421 5.421 3.8872

c [Å] 30.880 37.010 11.680

# of adjacent CuO2 planes

2 3 2

Tc [K] 91 110 92Bi2212

Bi2Sr2CaCu2O8+x

Bi2223Bi2Sr2Ca2Cu3O10+x

Y123YBa2Cu3O7-x

3 CuO2 planes

2 CuO2 planes

CuO chains

2 CuO2 planes

O

Ca

Cu

Sr

Bi

O

Cu

Y

Ba

Previously, in lecture 8 - HTS materials for applications

1.02b

a

in BSCCO1.001b

a

in YBCO

Grain Boundaries in Y123

Grain boundaries in Y123

Hilgenkamp and Mannhart, RMP 74 (2002) 485

[001] tilt boundary

[100] tilt boundary

[100] twist boundary

For angles above 8-10°, the JcGB is reduced by a factor >100 !!

In order to get high Jc in the conductor, the c-axis texturing is not enough

We do need also texturing in the ab plane

HTS conductors: texturing in Bi2223 and Y123

Both in Bi2223 and Y123, c-axis texturing is required due to the anisotropy of the properties //ab and //c

Because of the Jc dependence on the GB angle in the ab plane, also in-plane texturing is required for Y123

a

b

b

ba

a

b

ab

a

a

b

a

b

a

b

a

b

a a

b

a

b

current current

Bi2223 Y123

This biaxial texture is required over kilometers!!

YBCO (REBCO) coated conductors

Ag cap layer

Cu stabilisation

REBCO layer metallic substratebuffer layers

~1 µm of REBCO in a ~100 µm thick tape

Biaxial texturing – within < 3° – is obtained

a

b

a

b

a

b

a

b

a a

b

a

b

Looking from above

The template is a metallic substrate coated with a multifunctional oxide barrier

Goyal et al., APL 69 (1996) 1795

Iijima et al., APL 60 (1992) 769

Presently produced by

• complex and expensive manufacturing process

• pronounced anisotropic behaviour

but with some also drawbacks:

The technology of REBCO coated conductorsAlternative approaches for growing epitaxial REBCO on flexible metallic substrates in km-lengths

Substrate texturing

RABiTS : Rolling-Assisted, Biaxially Textured Substrates

Texture is created in NiW by a rolling-and-recrystallization process

IBAD : Ion Beam Assisted DepositionA biaxially textured MgO layer is grown on polycrystalline Hastelloy

REBCO layer deposition

Physical routes

Chemical routes

PLD Pulsed Laser Deposition

RCE Reactive Co-Evaporation

MOD Metal-Organic Deposition

MOCVD Metal-Organic Chemical Vapor Dep.

REBCO conductor technology: RABiTS template

RABiTS : Rolling-Assisted, Biaxially Textured Substrates

• [100] cube texture is created in the NiW substrate by a rolling-and-recrystallization process

• Several epitaxial buffer layers are needed to provide a lattice matched surface for growing the HTS layer

REBCO conductor technology: IBAD template

IBAD : Ion Beam Assisted Deposition

• A biaxially textured MgO layer is grown on a polycrystalline Hastelloy tape

• Several other buffer layers are needed to provide a lattice matched surface for growing the HTS layer

Performance overview: Jc(s.f.,77K) vs. Jc(19T,4.2K)

2.5 10 1005

10

100

STI

15 mol % Zr

SuperPower M3

J c-la

yer

(19

T,4

.2K

) [k

A/m

m2]

Jc-layer

(s.f.,77K) [kA/mm2]

BHTS T150

BHTS T2289

BHTS T2291

BHTS T003

SuperOx

AMSC

Fujikura

SuNAM

SuperPower M4

BHTS T002

BHTS T2290

15 mol. % Zr-added (Y,Gd)BCO Xu et al., APL Mat. 2 (2014) 046111

Artificial pinning to enhance REBCO performanceIntroduction of artificial nano-defects to control vortex pinning, reduce anisotropy and enhance performance

BaZrO3 (BZO) precipitates are in form of nano-columns oriented along the c-axis

Driscoll et al., Nat. Mat. 3 (2004) 439

Goyal et al., SuST 18 (2005) 1533 0 30 60 90 120 150 180 210 240

2

3

4

5

6

7

8

9

10

@ 77 K, 1 T

J c (

1 T

,77

K)

[kA

/mm

2]

Angle between field and c-axis [°]

standard REBCO

REBCO + BZO nanocolumns

0 30 60 90 120 150 180 210 2402

3

4

5

6

7

8

9

10

@ 77 K, 1 T

J c (

1 T

,77

K)

[kA

/mm

2]

Angle between field and c-axis [°]

standard REBCO

Selvamanickam et al., IEEE TAS 21 (2011) 3049

On the BZO nanorods morphology

Average BZO size 5.5 nmAverage spacing ~ 12 nmDensity = 6.9 × 1011 cm-2

Selvamanickam el al., APL 106 (2015) 032601

No loss of BZO alignment in 2.2 μmthick films

Engineering vs. superconducting layer performance

0 5 10 15 20100

1000

5000

Bi2223

Bi2212

BHTS REBCO B tape - UNIGE

OST Bi2212 - Larbalestier et al.(2014)

Sumitomo Bi2223 B tape - UNIGE

@ 4.2 K

J eng [

A/m

m2]

Magnetic field [T]

REBCO

Engineering current density

0 5 10 15 20

1

10

100

1000

Bi2223

Bi2212

BHTS REBCO B tape - UNIGE

OST Bi2212 - Larbalestier et al.(2014)

Sumitomo Bi2223 B tape - UNIGE

@ 4.2 K

J c [kA

/mm

2]

Magnetic field [T]

REBCO

Critical current density

REBCO and Bi2223 tapes retain the anisotropic properties of the superconductor

Data shown here correspond to the unfavorable orientation wrt the field

The in-field properties of Bi2212 wires are fully isotropic

Industrial superconductors: Je Comparison

http://fs.magnet.fsu.edu/~lee/plot/plot.htm

ce

tot

IJ

S

Industrial superconductors

React&Wind vs Wind&React

React&Wind Wind&React

in situ MgB2

Nb3Sn

IMD MgB2

Bi2212

NbTi

ex situ MgB2

Bi2223

Y123

How to choose the superconductor: Performance vs Cost

0 5 10 15 20 250

50

100

150

200

@ 4.2 K Nb3SnNb-Ti

Bi2212

YBCO B//ab

YBCO B//c

Pri

ce/p

erf

orm

ance

($

/kA

m)

Magnetic field (T)

Copper

Adapted from B. Seeber, IEEE TASC 28 (2018) 6900305

engJ kkA m g

$ $

Superconductor TechnologyBasic design and operation issues of a superconducting device

Superconducting magnets, field shapes and winding configurations

• Solenoids (NMR, MRI and laboratory magnets)

• Transverse fields (particle accelerators)

• Toroids (fusion magnets)

Solenoids: concepts and design

0

34C

Idl rB r

r

Biot-Savart law

* Overall current density, normalized to the winding section including wire matrix and insulation

0 ,B JaF

In the case of a solenoid

2 2

02

, ln1 1

F

l

a

b

a with and

2 ( )

NIJ

l b a

where *

B0

A given field can always be made by a short fat coil or a long thin one

/b a

l

a

2 22 ( )V l b a

3 22 ( 1)a

Coil geometry and shape factor

0 ,B JaF

B0Bw

Maximum field on the winding

l

a

b

a

and have an influence on the field uniformity

At the exercise session: how to choose and when designing a solenoid

B0

Homogeneity of the field along z

0 ,B JaF

b

a

l

a

l+z

l-z

zB 1

1,

2JaF 2

1,

2JaF

where and

z

Bz

How to calculate the variation of field along the axis of a solenoid

1

l z

a

2

l z

a

Homogeneity of the field along z

Along the solenoid axis

2 4 6

0 2 4 61 ...z

z z zB B E E E

a a a

By suitable adjustment of coil shape, one may reduce an error coefficient to zero

2 4 0E E

This notched solenoid is of sixth order

2

2 20

1 1

2 !

nz

n n

d BE

B n dz

A 32 T all-superconducting magnet at NHMFL, US

Subdivide the winding into a numberof concentric sections to improve theefficiency of superconductor utilization

Each section operates at the maximumcurrent density allowed by the localfield level

All sections take the same current, buteach section has its own J, and

General guidelines for magnet design

Bibliography

Papers cited in the slides

WilsonSuperconducting MagnetsChapter 3

Rogalla & Kes100 Years of SuperconductivityChapter 11 Section 5 (Y123)