Temperature Response of BaZrO₃-Inclusion to YBa₂Cu₃O_7−δ Probed by Magneto-Transport Measurements

Abstract

This paper reflects a simple and practically scalable technique, in which attempts have been made for preparation of fine BaZrO₃ (BZO) as defects in YBa₂Cu₃O_7−δ (YBCO) superconductor, to enhance superconducting properties. The texture growth of YBCO + xBZO (x=1.0,2.5,5.0 and 10.0 wt.%) composites has been made through solid-state reaction route by employing calcined YBCO and sub-micron sized powders of BZO. The phase formation, texture and grain alignment were analyzed using XRD and SEM. The magnetoresistivity data obtained as a function of temperature (T) in the tail region shows two key features: first an anomalous secondary peak at $T_{c_{\mathrm{on}2}}$ well below 92 K as a function of BZO content with varying magnetic fields, and secondly a drop in global resistivity transition temperature (T _c0) following the incorporation of excess BZO to the grain boundaries. Impurities appear to reduce $T_{c_{\mathrm{on}2}}$ greatly to the lower-temperature values as a function of BZO content and to influence the onset of $T_{c_{\mathrm{on}1}}$ in presence of varying magnetic fields. The findings of this investigation suggest the presence of multiple transition temperatures in the composites.