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Revisiting heat capacity of bulk polycrystalline YBa2Cu3O7-δ

In this letter, we present the superconducting property characterization of a phase pure reasonably good quality YBa2Cu3O7-δ sample. Studied compound is crystallized in orthorhombic Pmmm space group with lattice parameters a, b, and c are 3.829(2) Å, 3.887(1) Å and 11.666(3) Å respectively. Bulk superconductivity is observed below 90K as evidenced by resistivity and dc/ac magnetization measurements. The resistivity under magnetic field (ρTH) measurements showed clearly both the intra-grain and inter-grain transitions, which are supplemented by detailed (varying frequency and amplitude) ac susceptibility studies as well. The upper critical field at 0K i.e., Hc2(0) being determined from ρTH measurements with 50% criteria of resistivity drope is ~ 70 Tesla. Studied polycrystalline YBa2Cu3O7-δ is subjected to detailed heat capacity (CP) studies. Cp exhibited well defined anomaly at below 90 K, which decreases with applied field. Though the Cp anomaly/peak at Tc reduces with applied field, the same is not completely suppressed in high applied fields of up to 12 Tesla. The Sommerfeld constant (γ) and Debye temperature (ΘD) as determined from low temperature fitting of CP(T) data to Sommerfeld-Debye model, are 10.65 mJ/mole-K2 and 312.3 K respectively. The results are compared with existing literature on bulk polycrystalline superconducting YBa2Cu3O7-δ sample