Dependence of the flux-creep time scale on sample size for melt-textured YBa{sub 2}Cu{sub 3}O{sub 7} by ac-susceptibility measurements
- Department of Physics and National Laboratory of Solid State Microstructures, Center for Advanced Studies in Science and Technology of Microstructures, Nanjing University, Nanjing, 210008, People`s Republic of (China)
- Shanghai Institute of Mettallurgy, Academia Sinica, Shanghai 20050, People`s Republic of (China)
The complex ac susceptibility {chi} was measured as a function of temperature {ital T}, ac field frequency {ital f}, and amplitude {ital H}{sub ac} for three textured YBa{sub 2}Cu{sub 3}O{sub 7} samples with different sizes {ital d}. The effects of {ital f} and {ital H}{sub ac} on the peak temperature {ital T}{sub {ital p}} in {chi}{double_prime} were analyzed based on nonlinear flux diffusion theory. The current-density- ({ital j}-) dependent effective activation barriers {ital U}({ital j}){proportional_to}ln({ital j}{sub 0}/{ital j}) have been extracted in a time window of milliseconds and are the same as those obtained in other time windows. Flux-creep time scales {ital t}{sub 0} of 10{sup {minus}5} and 10{sup {minus}7} s have been extracted for the large ({ital d}{approx_equal}1 mm) and small ({ital d}{approx_equal}10 {mu}m) samples, respectively. The fact that {ital t}{sub 0} increases with sample size shows that it is a macroscopic quantity, as predicted by the nonlinear flux diffusion theory. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 283876
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 53, Issue 17; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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