Magnetization hysteresis of quench-melt-growth processed YBa 2Cu 3O 7 in high fields up to 23 T

Abstract

Using a newly established vibrating-sample magnetometer (VSM) combined with a hybrid magnet, the magnetic hysteresis of a quench-melt-growth processed YBa 2Cu 3O 7 has been measured in wide temperature and field ranges (4.2 ≤ T < 91 K and 0 ≤ H < 23 T). The magnetization loops show different characteristics in different temperature regions. At high temperatures above 70 K; magnetization curves show a normal characteristic and can be scaled using the remanent magnetization and the irreversibility field as scaling parameters. A magnetization anomaly often called the fishtail effect is observed only in an intermediate temperature region (typically 40 ≤ T < 70 K). In this temperature region, using irreversibility field and the peak magnetization in the fishtail effect as the scaling parameters, magnetic hysteresis is well scaled in fields up to 23 T. At low temperatures below 40 K, magnetization curves indicate a weak dependence of the critical current on fields up to 23 T. However, it is difficult for them to find the appropriate scaling parameters. The fishtail effect observed in the present experiments shows a different behavior than reported so far. In particular, the peak field in the peak effect first increased very slowly with decreasing temperature and then decreased when temperature was reduced from 50 to 40 K. The peak effect was absent below 40 K.