Melting of the flux line lattice observed by specific heat experiments in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}
- Universite de Geneve (Switzerland)
High resolution adiabatic specific heat experiments on YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (0{le}{delta}{le}0.05) are performed in magnetic fields from 0 to 14 T (B{parallel}c and B{perpendicular}c). In a 0.3 gram, twinned crystal with strong pinning, a step is consistently observed at the melting temperature T{sub m} of the vortex solid up to a critical point that depends on {delta}. The field B{sub m} and step temperature T{sub m} obey the relation B{sub m}=B{sub m0}({delta})(1-T{sub m}/T{sub c}){sup {approx}4/3}. The anisotropy of B{sub m} and that of the upper critical field B{sub c2} are found to be equal. Alternatively, in a 18 mg, twinned crystal of high purity with low pinning, first-order-like specific heat peaks are observed on the melting line from 8 to 14 T. The entropy under these peaks is {approx}0.5 k{sub B}/vortex/bilayer. These characteristic features are attributed to the melting of a vortex glass in the former case and that of a vortex lattice in the latter case.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 443631
- Report Number(s):
- CONF-960808-; ISSN 0022-2291; TRN: 97:000865-0004
- Journal Information:
- Journal of Low Temperature Physics, Vol. 105, Issue 5-6; Conference: 3. international conference on physics and chemistry of molecular and oxide superconductors, Karlsruhe (Germany), 2-6 Aug 1996; Other Information: PBD: Dec 1996
- Country of Publication:
- United States
- Language:
- English
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