Field Induced Vanishing of the Vortex Glass Temperature in Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8} Thin Films
- Institute COMPAS and Faculty of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam (The Netherlands)
- National Laboratory for Superconductivity, Institute of Physics, P.O.Box 603, Beijing 100080, People`s Republic of (China)
The current density j{sub s} and relaxation rate Q have been measured on a ring shaped Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8} film between 4.2K and the irreversibility temperature in magnetic fields up to 7T. The temperature and field dependent exponent {mu}(T,B{sub e}) used to parametrize the activation energy U in the form U(j{sub s},T,B{sub e})= (U{sub c}/{mu})[( j{sub c}/j{sub s}){sup {mu}}{minus}1] is determined for many different fields. In the B{sub e}{minus}T phase diagram we associate the {mu}=0 line with the glass temperature T{sub g} and find that T{sub g} essentially drops to 0K at B{sub e}{approx}0.7 T, which indicates a dimensional crossover at this field. The {mu}{gt}0 region (B{sub e}{lt}0.7 T, T{le}55 K) corresponds to 3D elastic vortex motin while the {mu}{lt}0 region corresponds to 2D dislocation mediated flux creep. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 560637
- Journal Information:
- Physical Review Letters, Vol. 79, Issue 8; Other Information: PBD: Aug 1997
- Country of Publication:
- United States
- Language:
- English
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