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Title: Paramagnetic Meissner effect analyzed by second harmonics of the magnetic susceptibility: Consistency with a ground state carrying spontaneous currents

Abstract

It has been reported recently by Braunisch [ital et] [ital al]. [Phys. Rev. Lett. 68, 1908 (1992)] that some ceramic high-[ital T][sub [ital c]] superconductors (HTSC's) exhibit a paramagnetic signal if cooled through the superconducting transition temperature in small external magnetic dc fields ([ital H][sub dc][lt]1 Oe). In the present work, this paramagnetic Meissner effect (PME) is experimentally confirmed and further experimental details are reported on this phenomenon. This is accomplished by applying a recently developed compensation technique based on the measurement of the second harmonic of the magnetic ac susceptibility in external dc fields. This technique allows one to detect sensitively the dc magnetization of a HTSC sample and makes it possible to observe the PME under conditions where its dc superconducting-quantum-interference-device signal is totally masked by the dominating diamagnetic behavior of most of the sample. The experiments were performed on melt processed Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8[minus][ital x]] samples, some of which did not exhibit the PME. Thus, a comparison was possible between samples with and without the PME, subjected to different field-cooling procedures. The experimental results are consistent with the occurrence of a reversible transition into a PME state carrying spontaneous orbital currents resulting in corresponding paramagneticmore » moments, which can be reversibly aligned by small external dc fields. This PME state is attributed to loops containing relatively strong weak links, which are able to remain superconducting close to the bulk [ital T][sub [ital c]] of the grains (e.g., at [ital T]/[ital T][sub [ital c]]=0.9) and in external dc fields of at least 30 Oe.« less

Authors:
; ;  [1]
  1. Fakultaet fuer Physik, Universitaet Konstanz, D-78464 Konstanz (Germany)
Publication Date:
OSTI Identifier:
5429746
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter; (United States)
Additional Journal Information:
Journal Volume: 48:5; Journal ID: ISSN 0163-1829
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BISMUTH OXIDES; MEISSNER-OCHSENFELD EFFECT; PARAMAGNETISM; CALCIUM OXIDES; COPPER OXIDES; HIGH-TC SUPERCONDUCTORS; STRONTIUM OXIDES; DIAMAGNETISM; GRAIN BOUNDARIES; GRANULAR MATERIALS; GROUND STATES; MAGNETIC SUSCEPTIBILITY; TEMPERATURE DEPENDENCE; TRANSITION TEMPERATURE; ALKALINE EARTH METAL COMPOUNDS; BISMUTH COMPOUNDS; CALCIUM COMPOUNDS; CHALCOGENIDES; COPPER COMPOUNDS; ENERGY LEVELS; MAGNETIC PROPERTIES; MAGNETISM; MATERIALS; MICROSTRUCTURE; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; STRONTIUM COMPOUNDS; SUPERCONDUCTORS; THERMODYNAMIC PROPERTIES; TRANSITION ELEMENT COMPOUNDS; 360207* - Ceramics, Cermets, & Refractories- Superconducting Properties- (1992-)

Citation Formats

Heinzel, C, Theilig, T, and Ziemann, P. Paramagnetic Meissner effect analyzed by second harmonics of the magnetic susceptibility: Consistency with a ground state carrying spontaneous currents. United States: N. p., 1993. Web. doi:10.1103/PhysRevB.48.3445.
Heinzel, C, Theilig, T, & Ziemann, P. Paramagnetic Meissner effect analyzed by second harmonics of the magnetic susceptibility: Consistency with a ground state carrying spontaneous currents. United States. https://doi.org/10.1103/PhysRevB.48.3445
Heinzel, C, Theilig, T, and Ziemann, P. 1993. "Paramagnetic Meissner effect analyzed by second harmonics of the magnetic susceptibility: Consistency with a ground state carrying spontaneous currents". United States. https://doi.org/10.1103/PhysRevB.48.3445.
@article{osti_5429746,
title = {Paramagnetic Meissner effect analyzed by second harmonics of the magnetic susceptibility: Consistency with a ground state carrying spontaneous currents},
author = {Heinzel, C and Theilig, T and Ziemann, P},
abstractNote = {It has been reported recently by Braunisch [ital et] [ital al]. [Phys. Rev. Lett. 68, 1908 (1992)] that some ceramic high-[ital T][sub [ital c]] superconductors (HTSC's) exhibit a paramagnetic signal if cooled through the superconducting transition temperature in small external magnetic dc fields ([ital H][sub dc][lt]1 Oe). In the present work, this paramagnetic Meissner effect (PME) is experimentally confirmed and further experimental details are reported on this phenomenon. This is accomplished by applying a recently developed compensation technique based on the measurement of the second harmonic of the magnetic ac susceptibility in external dc fields. This technique allows one to detect sensitively the dc magnetization of a HTSC sample and makes it possible to observe the PME under conditions where its dc superconducting-quantum-interference-device signal is totally masked by the dominating diamagnetic behavior of most of the sample. The experiments were performed on melt processed Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8[minus][ital x]] samples, some of which did not exhibit the PME. Thus, a comparison was possible between samples with and without the PME, subjected to different field-cooling procedures. The experimental results are consistent with the occurrence of a reversible transition into a PME state carrying spontaneous orbital currents resulting in corresponding paramagnetic moments, which can be reversibly aligned by small external dc fields. This PME state is attributed to loops containing relatively strong weak links, which are able to remain superconducting close to the bulk [ital T][sub [ital c]] of the grains (e.g., at [ital T]/[ital T][sub [ital c]]=0.9) and in external dc fields of at least 30 Oe.},
doi = {10.1103/PhysRevB.48.3445},
url = {https://www.osti.gov/biblio/5429746}, journal = {Physical Review, B: Condensed Matter; (United States)},
issn = {0163-1829},
number = ,
volume = 48:5,
place = {United States},
year = {1993},
month = {8}
}