Preferential position of order parameter and angular dependence of upper critical fields in Nb/NbZr multilayers

ABSTRACTThe angular dependence of the upper critical fields, Hc(θ) for a set of NbTi-Ge superlattices were studied at various temperatures. The behavior of Hc(θ) at lower temperatures deviates from the Tinkham expression which is expected to be valid only in the Ginzberg-Landau regime close to Tc. We examine a model for calculating Hc(θ) involving the lowest eigenvalue of the gauge invariant diffusion equation (subject to boundary conditions appropriate to a slab) in the de Gennes expression for the upper critical field of a dirty superconductor at all temperatures. The disorder related localization and interaction effects as well, as the paramagnetic limiting effect, are also considered.

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Angular dependence of upper critical fields in Nb/Nb1-xZrx-multilayers

Physica B Condensed Matter ◽

10.1016/0921-4526(94)91710-8 ◽

1994 ◽

Vol 194-196 ◽

pp. 2421-2422 ◽

Cited By ~ 1

Author(s):

Y. Kuwasawa ◽

T. Nojima ◽

S. Nakano ◽

K. Takanaka

Keyword(s):

Angular Dependence ◽

Critical Fields ◽

Upper Critical Fields

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Changes in the upper critical fields and critical currents of Nb3Sn and V3Ga owing to neutron radiation damage

Applied Physics Letters ◽

10.1063/1.89277 ◽

1977 ◽

Vol 30 (12) ◽

pp. 662-664 ◽

Cited By ~ 12

Author(s):

C. L. Snead

Keyword(s):

Radiation Damage ◽

Neutron Radiation ◽

Critical Currents ◽

Critical Fields ◽

Upper Critical Fields ◽

Neutron Radiation Damage

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Angular dependence of magnetization reversal critical fields in individual grains of REFeB magnets

Journal of Magnetism and Magnetic Materials ◽

10.1016/0304-8853(94)01264-4 ◽

1995 ◽

Vol 140-144 ◽

pp. 1063-1064 ◽

Cited By ~ 3

Author(s):

Yu.G. Pastushenkov

Keyword(s):

Angular Dependence ◽

Magnetization Reversal ◽

Critical Fields ◽

Individual Grains

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A novel technique for synthesizing MgB2thin films with high upper critical fields

Superconductor Science and Technology ◽

10.1088/0953-2048/21/8/085009 ◽

2008 ◽

Vol 21 (8) ◽

pp. 085009 ◽

Cited By ~ 8

Author(s):

Y Shen ◽

R Gandikota ◽

R K Singh ◽

F L Hunte ◽

J Jaroszynski ◽

...

Keyword(s):

Critical Fields ◽

Novel Technique ◽

Upper Critical Fields

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Anisotropic Upper Critical Fields of Highly Oriented Bi-Sr-Ca-Cu-O Thin Films Prepared by Coevaporation

Japanese Journal of Applied Physics ◽

10.1143/jjap.27.l1094 ◽

1988 ◽

Vol 27 (Part 2, No. 6) ◽

pp. L1094-L1096 ◽

Cited By ~ 23

Author(s):

Tsutomu Yoshitake ◽

Tetsuro Satoh ◽

Yoshimi Kubo ◽

Takashi Manako ◽

Hitoshi Igarashi

Keyword(s):

Thin Films ◽

Critical Fields ◽

Upper Critical Fields

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Structure and Functional Properties of Bulk MgB2 Superconductors Synthesized and Sintered under Pressure

Materials Science Forum ◽

10.4028/www.scientific.net/msf.792.21 ◽

2014 ◽

Vol 792 ◽

pp. 21-26 ◽

Cited By ~ 2

Author(s):

Tatiana Prikhna ◽

Michael Eisterer ◽

Wolfgang Gawalek ◽

Athanasios G. Mamalis ◽

Artem Kozyrev ◽

...

Keyword(s):

Critical Current ◽

Material Structure ◽

Bulk Materials ◽

Critical Fields ◽

Current Densities ◽

Upper Critical Fields ◽

Irreversibility Fields ◽

Grain Boundary Pinning ◽

Effect Of Oxygen ◽

Oxygen Impurities

The high pressure (50 MPa - 2 GPa) – high temperature synthesized MgB2 bulk materials are characterized by nearly theoretical density (1-2% porosity), 80-98% connectivity, extremely high critical current densities (e.g. at 20 K, in 0–1 T jc=1.3–1.0 MA·cm-2 (with 10% SiC) and jc= 0.92 – 0.73 MA·cm-2 (without doping)), large irreversibility fields (Birr(18.4 K) =15 T and Birr (0 K) = 32.5 T) and high upper critical fields (Bc2 (22 K) =15 T and Bc2(0 K) ~ 42.1 T). The transformation of grain boundary pinning to point pinning in MgB2-based materials with increasing manufacturing temperature (from 800 to 1050 oC) under pressures from 0.1 to 2 GPa correlates well with an increase in critical current density in low external magnetic fields caused by the redistribution of boron and the oxygen impurities in the material structure. As the manufacturing temperature increases, the discontinuous oxygen enriched layers transform into distinct Mg-B-O inclusions and the size and amount of inclusions of higher magnesium borides MgBX (X>4) are reduced. The effect of oxygen and boron redistribution can be enhanced by Ti or SiC additions.

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