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Specific heat of Bi2Sr2CaCu2Ox versus oxygen content (0≤B≤14T)

1994; Elsevier BV; Volume: 194-196; Linguagem: Inglês

10.1016/0921-4526(94)91248-3

1873-2135

A. Junod, K.-Q. Wang, G. Triscone, J. Müller,

Magnetic properties of thin films

In order to characterize more precisely the superconducting transition of a quasi-2D superconductor, we quenched polycrystalline samples of Bi2Sr2CaCu2Ox from various locations of the (T; p(O2)) equilibrium diagram. A well-defined specific heat peak at Tc is observed with 0.01% resolution for the samples with the highest Tc. The samples with lower Tc's provide strong support to the normal-state background determined by an analysis of the data including phonon and fluctuation terms. We do not find any indication of a mean-field jump within experimental uncertainty, in stark contrast to YBa2Cu3O7. The application of a 14 Tesla field depresses the total specific heat by 0.54% only at T(peak)=92.5K, but this effect reduces to less than 0.03% already ±8K away from Tc. On passing the irreversibility line, no anomaly in the specific heat is detected at the 0.01% level.