Magnetically modulated microwave absorption studies on high-T-c powdered materials

摘要

Magnetically modulated microwave absorption (MMA) is performed on powdered high-T-c Bi2Sr2Ca2Cu3Oy, Bi2Sr2Ca1Cu2Oy and Y1Ba2Cu3Oy materials. The temperature dependence of the zero field microwave absorption maximum and low field hysteresis is presented. It is observed that the zero field line and low field hysteresis depend on the particle size of powdered materials. We show that a model, which combines a model based on the existence of a critical state with pinning and depinning of fluxons during a modulation cycle and a weak link model, can account for the observed temperature and particle-size dependence of zero field line and hysteresis. (C) 1998 Elsevier Science B.V. All rights reserved. [References: 24]