Improvement of critical current density in YBaCuFO compounds by addition of platinum

Abstract

Platinum added YBaCuFO compounds with nominal composition YBa 2Cu 3F 0.4O xPt y { y=0, 0.3, 0.5} were prepared by a partial melt process performed at lower temperature than the conventional melt process. Optical micrograph observations showed that Y 2BaCuO 5 (211) particles increase in density and are dispersed finely when increasing the doping of Pt up to 0.3 wt%. For the 0.5 wt% Pt sample, however, the size of the 211 particles became larger than in the samples containing less than 0.3 wt% Pt. The magnetization was measured using a SQUID magnetometer in the temperature range 20–77 K under magnetic fields B e up to 1 T. The magnetization M also increased with increasing quantity of platinum up to 0.3 wt%. The J c values estimated from the width of the magnetization curves were 9.8×10 7 A/m 2 for the 0.3 wt% Pt sample and 5.4×107 A/m 2 for the undoped sample at 77 K and B e=0.8 T. In addition, the whereabouts of the platinum in the quenched samples was investigated by using electron spectroscopy for chemical analysis (ESCA).