DocumentCode :
942756
Title :
A comparison of twin boundary pinning in nearly fully stoichiometric and oxygen deficient YBa/sub 2/Cu/sub 3/O/sub 7- delta /
Author :
Fleshler, S. ; Kwok, W.K. ; Welp, U. ; Downey, J. ; Crabtree, G.W.
Author_Institution :
Argonne Nat. Lab., IL, USA
Volume :
3
Issue :
1
fYear :
1993
fDate :
3/1/1993 12:00:00 AM
Firstpage :
1483
Lastpage :
1486
Abstract :
The angular dependence of the magnetoresistance was measured on the same single crystal of YBa/sub 2/Cu/sub 3/O/sub 7- delta / prepared initially with a superconducting transition temperature of 93 K and then annealed to obtain a transition temperature of 56.9 K. A second oxygen deficient sample was produced with a transition temperature of 57.0 K and nearly identical transport characteristics. Twin boundary pinning superimposed on flux flow behavior was observed in both the 56.9 K and 93.0 K states for magnetic field rotation in the ab plane. For magnetic field rotations off the c-axis, twin boundary pinning is observed only for the nearly stoichiometric state. The broadening of the resistive transition in magnetic field (H//c) is observed to occur over a much larger interval of reduced temperature in the deoxygenated state. The enhanced broadening of the resistive transition in magnetic field and absence of twin boundary pinning may indicate that the vortex system is two-dimensional, and, in general, defects are rendered ineffective in pinning due to the absence of three-dimensional collective elastic effects.<>
Keywords :
barium compounds; flux flow; flux pinning; high-temperature superconductors; magnetoresistance; twin boundaries; yttrium compounds; 56.9 K; 57.0 K; 93 K; O deficient; YBa/sub 2/Cu/sub 3/O/sub 7- delta /; angular dependence; defects; deoxygenated state; flux flow behavior; high temperature superconductor; magnetic field rotation; magnetoresistance; nearly fully stoichiometric; single crystal; superconducting transition temperature; three-dimensional collective elastic effects; twin boundary pinning; vortex system; Anisotropic magnetoresistance; Crystals; High temperature superconductors; Magnetic anisotropy; Magnetic fields; Materials science and technology; Oxygen; Perpendicular magnetic anisotropy; Superconducting magnets; Superconducting transition temperature;
fLanguage :
English
Journal_Title :
Applied Superconductivity, IEEE Transactions on
Publisher :
ieee
ISSN :
1051-8223
Type :
jour
DOI :
10.1109/77.233614
Filename :
233614
Link To Document :
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