Naslov
Changes in irreversibility line, anisotropy, and condensation energy by oxygen depletion of YBa2Cu3O7-delta

Autori
Babić, Dinko ; Cooper, John Robert ; Hodby, J.W. ; Changkang, Chen

Izvornik
Physical review. B, Condensed matter and materials physics (1098-0121) 60 (1999), 1; 698-706

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
superconductivity ; irreversibility

Sažetak
We report results of magnetization measurements on the same YBa2Cu3O7−δ crystal for a range of δ values 0.03<~δ<~0.35, in magnetic fields up to 120 kOe, applied parallel or perpendicular to the CuO2 planes. Zero-field resistivity anisotropy measurements have also been made for the same values of δ. The irreversibility line Hirr falls by over a factor of 10 in the range of δ studied, and there is a similar strong decrease in superconducting condensation energy associated with the growth of the normal-state pseudogap in under-doped cuprates. On the other hand, the anisotropy in Hirr and the room-temperature resistivity anisotropy only increase by a factor of 2. Evidence that for our crystals the so-called “vortex lattice melting line” Hm(T)≈Hirr(T) is presented. There is also a large field and temperature region where the reversible magnetization varies as H−1/2 and its magnitude corresponds to a free-energy density of kBT in a certain field-dependent correlation volume. Many of the results are consistent with the presence of critical thermodynamic fluctuations described by the three-dimensional XY model ; these are probably enhanced when the field along the c axis is greater than 10 kOe.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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