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Title: Critical state in a circular two-dimensional superconductor and magnetization of thin Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in a transverse field

Abstract

Precise measurements of the magnetization of circular epitaxial Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in a transverse magnetic field are performed and analyzed within the framework of the recently presented critical state model (CSM) in the two-dimensional superconductor. Restrictions on the reliability of the model are considered. It has been found that the original CSM, based on Bean`s limitation on the critical current density {ital J}{sub {ital c}}=const, describes well the temperature and field dependences of the film magnetization in a low field (until the full disappearance of the flux-free region in the film) under the condition {ital B}{sup *}{much_gt}{mu}{sub 0}{ital dJ}{sub {ital c}}ln({radical}{ital Rd} /{lambda}), where {ital B}{sup *} is the characteristic field of the critical current drop in a strong field, {lambda} is the penetration depth, {ital d} is the thickness, and {ital R} is the radius of the film, respectively. In the strong field an exponential or power suppression of the critical current is observed and the model under question is extended to this region. The problem of a lower critical field related to thin films is also discussed. The paramagnetic response demonstrated by all our films in field-cooled measurements, which has muchmore » in common with the Wohlleben effect, was investigated and the conclusion was drawn that this artifact is caused by the temperature-dependent stray field of the magnetometer parts.« less

Authors:
; ;  [1];  [2]
  1. Department of Quantum Electronics, Moscow Engineering Physics Institute, Kashirskoe shosse 31, 115409, Moscow (Russian Federation)
  2. Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980, Dubna, Moscow region (Russian Federation)
Publication Date:
OSTI Identifier:
250489
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter
Additional Journal Information:
Journal Volume: 52; Journal Issue: 13; Other Information: PBD: 1 Oct 1995
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; SUPERCONDUCTING FILMS; MAGNETIZATION; COPPER OXIDES; BARIUM OXIDES; YTTRIUM OXIDES; CERIUM OXIDES; NEODYMIUM OXIDES; HIGH-TC SUPERCONDUCTORS; EPITAXY; MAGNETIC FIELDS; TWO-DIMENSIONAL CALCULATIONS

Citation Formats

Kuznetsov, A V, Ivanov, A A, Eremenko, D V, and Trofimov, V N. Critical state in a circular two-dimensional superconductor and magnetization of thin Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in a transverse field. United States: N. p., 1995. Web. doi:10.1103/PhysRevB.52.9637.
Kuznetsov, A V, Ivanov, A A, Eremenko, D V, & Trofimov, V N. Critical state in a circular two-dimensional superconductor and magnetization of thin Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in a transverse field. United States. https://doi.org/10.1103/PhysRevB.52.9637
Kuznetsov, A V, Ivanov, A A, Eremenko, D V, and Trofimov, V N. Sun . "Critical state in a circular two-dimensional superconductor and magnetization of thin Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in a transverse field". United States. https://doi.org/10.1103/PhysRevB.52.9637.
@article{osti_250489,
title = {Critical state in a circular two-dimensional superconductor and magnetization of thin Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in a transverse field},
author = {Kuznetsov, A V and Ivanov, A A and Eremenko, D V and Trofimov, V N},
abstractNote = {Precise measurements of the magnetization of circular epitaxial Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in a transverse magnetic field are performed and analyzed within the framework of the recently presented critical state model (CSM) in the two-dimensional superconductor. Restrictions on the reliability of the model are considered. It has been found that the original CSM, based on Bean`s limitation on the critical current density {ital J}{sub {ital c}}=const, describes well the temperature and field dependences of the film magnetization in a low field (until the full disappearance of the flux-free region in the film) under the condition {ital B}{sup *}{much_gt}{mu}{sub 0}{ital dJ}{sub {ital c}}ln({radical}{ital Rd} /{lambda}), where {ital B}{sup *} is the characteristic field of the critical current drop in a strong field, {lambda} is the penetration depth, {ital d} is the thickness, and {ital R} is the radius of the film, respectively. In the strong field an exponential or power suppression of the critical current is observed and the model under question is extended to this region. The problem of a lower critical field related to thin films is also discussed. The paramagnetic response demonstrated by all our films in field-cooled measurements, which has much in common with the Wohlleben effect, was investigated and the conclusion was drawn that this artifact is caused by the temperature-dependent stray field of the magnetometer parts.},
doi = {10.1103/PhysRevB.52.9637},
url = {https://www.osti.gov/biblio/250489}, journal = {Physical Review, B: Condensed Matter},
number = 13,
volume = 52,
place = {United States},
year = {1995},
month = {10}
}