高压高温处理对YNi_2B_2C晶界效应的影响

EFFECT OF THE TREATMENT UNDER HIGH-TEMPERATURE AND HIGH-PRESSURE ON YNi_2B_2C GRAIN BOUNDARY

在测量经压力处理的氩弧熔炼的YNi2 B2 C的金属间化合物超导体中场冷磁化率时 ,观察到升温磁化率曲线在临界温度附近有一个负的磁化率峰。通过研究高压高温处理对粉末样品和块状样品的场冷和零场冷却磁化率曲线的影响 ,认为场冷时反常负磁化率峰是由于样品中晶界的存在 ,从而导致晶粒间的弱连接所引起的 ,而不是由磁相变或超导和磁性共存现象所引起的。并认为有可能利用高压高温技术制备这类化合物和生长单晶。

Near critical temperature a negative peak in the field cooled measured upon warming magnetization curve was observed in YNi 2B 2C superconductor,which was prepared by melting in an arc furnace then treated under high pressure.The study of effect of high temperature and high pressure treatment on the magnetization curves of bulk and powder samples measured at zero field cooled and field cooled conditions shows that the negative magnetic peak in the field cooled magnetization comes from the grain boundary that leads a week link,but not from magnetic phase transition or the coexistence of superconductivity and magnetism.The result also demonstrates that the preparation and crystal growth of the material can be taken under high temperature and high pressere.