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Title: Magnetic levitation force and penetration depth in type-II superconductors

Abstract

The superconducting levitation force [ital F] acting on a magnet placed above a type-II superconductor in both Meissner and mixed states is calculated as a function of temperature, based upon the London model. A simple relationship between the levitation force and the London penetration depth [lambda] is found. In particular, in the limit of [ital a]/[lambda][much gt]1, where [ital a] is the separation between the magnet and the superconductor, [ital F] varies linearly with [lambda], regardless of the shape of the magnet. The temperature dependences of [lambda] and [ital F] are examined for various superconducting pairing states, including [ital s]-wave, [ital d]-wave, and [ital s]+[ital id] states. It is found that, at low temperatures, both [lambda] and [ital F] show an exponential temperature dependence for [ital s]-wave, linear-[ital T] for [ital d]-wave, and [ital T][sup 2] dependence in a wide low-temperature range for the [ital s]+[ital id] state with a dominant [ital d]-wave component. The magnetic force microscope (MFM) is proposed to accurately measure the temperature-dependent levitation force. It is shown that the microscopic size of the MFM tip enables one to obtain the intrinsic temperature-dependent penetration depth of a single grain, in spite of the overall quality of themore » superconducting sample.« less

Authors:
; ;  [1]
  1. Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77204 (United States)
Publication Date:
OSTI Identifier:
7060950
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter; (United States)
Additional Journal Information:
Journal Volume: 51:1; Journal ID: ISSN 0163-1829
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; TYPE-II SUPERCONDUCTORS; MAGNETIC PROPERTIES; D STATES; LONDON EQUATION; MIXED STATE; PENETRATION DEPTH; S STATES; TEMPERATURE DEPENDENCE; ENERGY LEVELS; EQUATIONS; PHYSICAL PROPERTIES; SUPERCONDUCTORS; 665411* - Basic Superconductivity Studies- (1992-)

Citation Formats

Xu, J H, Miller, Jr, J H, and Ting, C S. Magnetic levitation force and penetration depth in type-II superconductors. United States: N. p., 1995. Web. doi:10.1103/PhysRevB.51.424.
Xu, J H, Miller, Jr, J H, & Ting, C S. Magnetic levitation force and penetration depth in type-II superconductors. United States. https://doi.org/10.1103/PhysRevB.51.424
Xu, J H, Miller, Jr, J H, and Ting, C S. 1995. "Magnetic levitation force and penetration depth in type-II superconductors". United States. https://doi.org/10.1103/PhysRevB.51.424.
@article{osti_7060950,
title = {Magnetic levitation force and penetration depth in type-II superconductors},
author = {Xu, J H and Miller, Jr, J H and Ting, C S},
abstractNote = {The superconducting levitation force [ital F] acting on a magnet placed above a type-II superconductor in both Meissner and mixed states is calculated as a function of temperature, based upon the London model. A simple relationship between the levitation force and the London penetration depth [lambda] is found. In particular, in the limit of [ital a]/[lambda][much gt]1, where [ital a] is the separation between the magnet and the superconductor, [ital F] varies linearly with [lambda], regardless of the shape of the magnet. The temperature dependences of [lambda] and [ital F] are examined for various superconducting pairing states, including [ital s]-wave, [ital d]-wave, and [ital s]+[ital id] states. It is found that, at low temperatures, both [lambda] and [ital F] show an exponential temperature dependence for [ital s]-wave, linear-[ital T] for [ital d]-wave, and [ital T][sup 2] dependence in a wide low-temperature range for the [ital s]+[ital id] state with a dominant [ital d]-wave component. The magnetic force microscope (MFM) is proposed to accurately measure the temperature-dependent levitation force. It is shown that the microscopic size of the MFM tip enables one to obtain the intrinsic temperature-dependent penetration depth of a single grain, in spite of the overall quality of the superconducting sample.},
doi = {10.1103/PhysRevB.51.424},
url = {https://www.osti.gov/biblio/7060950}, journal = {Physical Review, B: Condensed Matter; (United States)},
issn = {0163-1829},
number = ,
volume = 51:1,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 1995},
month = {Sun Jan 01 00:00:00 EST 1995}
}