EFFECT OF NANO-SIZED Al2O3 ADDITION ON THE TRANSPORT CRITICAL CURRENT DENSITY OF BULK (Tl0.85Cr0.15)Sr2CaCu2O7-δ SUPERCONDUCTOR

Abstract

The effect of nano-sized Al₂O₃ addition on the transport critical current density of (Tl_0.85Cr_0.15)Sr₂CaCu₂O_7-δ (Tl-1212) superconductor was (Tl_0.85Cr_0.15)Sr₂CaCu₂O_7-δ (Al₂O₃)_x superconductor for x = 0.0 to investigated. The 0.05 wt.% were prepared using high purity oxide powders via solid state reaction method. Samples were studied by powder X-ray diffraction method, electrical resistance measurements, scanning electron microscopy (SEM) and Dispersive X-Ray Analysis (EDX). The zero resistance temperature, T_c-zero was found to decrease from 95 K to 87 K with increasing nano-sized Al₂O₃ addition. The temperature dependence of J_c of the non-added and Al₂O₃ added bulk samples were investigated. The J_c of the non-added bulk sample was 1320 mA/cm2 at 30 K while Jc of the (Tl_0.85Cr_0.15)Sr₂CaCu₂O_7-δ(Al₂O₃)0.02 bulk sample was 4090 mA/cm² at 30 K. Nano-sized Al2O3 added bulk samples showed a higher Jc (more than 3 times) compared with the non-added sample. This study showed that nano-sized Al₂O₃ could act as effective flux pinning centers and lead to the enhancement of J_c in Tl-1212 superconductors.