Rotational magnetic processes in YBa sub 2 Cu sub 3 O sub 7

Journal Article · Tue May 01 04:00:00 EDT 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.344858· OSTI ID:6837261

Liu, L; Kouvel, J S ^[1]; Brun, T O ^[2]

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1. Department of Physics, University of Illinois at Chicago, Illinois 60680 (USA)
2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (USA)

A polycrystalline superconducting thin-disk sample was rotated in a fixed field ({bold H}) at 4.2 K, and the vector magnitude and orientation of the total magnetization ({bold M}) were measured as the sample-rotation angle ({theta}) was slowly cycled between 0{degree} and 360{degree}. The measured {bold M} was decomposed into a penetrating (vortex) flux component {bold M}{sub {ital p}} that rotates rigidly with the sample at very small {theta} and a diamagnetic (shielding) component {bold M}{sub {ital d}} that stays antiparallel to {bold H}. As {theta} is raised, {bold M}{sub {ital p}} deviates from rigid rotation, and the deviations are very different for the zero-field-cooled (ZFC) and field-cooled (FC) states at the same {ital H}, indicating different distributions in the strengths of the initial pinning forces. However, {ital M}{sub {ital d}} is exactly the same for both states and closely equals {chi}{sub 0}{ital H}, where {chi}{sub 0} is the low-{ital H} (ZFC) diamagnetic susceptibility. At still higher {theta}, {bold M}{sub {ital p}} rotates up to some critical angle relative to {bold H}, where it remains as the sample continues to turn. This frictional motion of {bold M}{sub {ital p}} relative to the sample presumably derives from a sequential hopping of vortices between pinning centers.

• OSTI ID: 6837261
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 67:9; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
DIAMAGNETISM
MAGNETIC PROPERTIES
MAGNETISM
MAGNETIZATION
MOTION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLYCRYSTALS
ROTATION
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
ULTRALOW TEMPERATURE
VORTICES
YTTRIUM COMPOUNDS
YTTRIUM OXIDES