Irreversibility line in YBa{sub 2}Cu{sub 3}O{sub 7} thin films: Correlation of transport and magnetic behavior
- Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States)
- Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)
- Laboratoire des Solides Irradies, Ecole Polytechnique, 91128 Palaiseau (France)
- Superconductivity Technology Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Using magnetic and magnetotransport measurements, we show that a YBa{sub 2}Cu{sub 3}O{sub 7} thin-film sample has a single irreversibility line (IRL), which is the same as the vortex-glass-transition phase boundary. Results suggest that the effects of pinning persist above the glass-transition temperature {ital T}{sub {ital g}}, and that it is the loss of critical-current density {ital J}{sub {ital c}} rather than an onset of reversible magnetic behavior that characterizes the vortex-glass transition. Measurements of dc magnetization are shown to confirm a theoretical model that explains why the determination of {ital T}{sub {ital g}} requires that field-cooled data be collected on cooling (FCC) rather than on warming (FCW), as is frequently done. The use of the ac susceptibility response for measuring {ital T}{sub {ital g}} is shown to be a valid measure only at low frequency. This is because both the fundamental-frequency and third-harmonic ac susceptibilities measure the onset of ac flux penetration rather than the onset of irreversibility. The frequency dependence of the onset temperature of ac flux penetration ({ital T}{sub on}) is shown to follow the vortex-glass-model dependence {ital T}{sub on}={ital C}(2{pi}{ital f}){sup {l_brace}1/[({ital z}{minus}1){nu}]{r_brace}}+{ital T}{sub {ital g}}, with values of {ital z} and {nu} consistent with those determined from scaling of the magnetotransport data.
- Research Organization:
- Purdue Univ., West Lafayette, IN (United States)
- DOE Contract Number:
- FG02-90ER45427; W-7405-ENG-82
- OSTI ID:
- 142598
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 49, Issue 9; Other Information: PBD: 1 Mar 1994
- Country of Publication:
- United States
- Language:
- English
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