Inter- and intragrain critical currents in a dense YBa2Cu3O7 ceramic

Abstract

The AC susceptibility and magnetisation were used to study the inter- and intragrain critical currents in a dense, low resistivity YBa2Cu3O7 ceramic in the temperature range 75-90 K. It is found that the magnetic-field dependence of the peaks in the imaginary part of the AC susceptibility can be used to determine both the inter- and intragrain critical currents. The relation between the field dependence of the intergrain peak in the imaginary susceptibility and the intergrain critical current has been verified by measuring the critical transport currents for two samples at 77.3 K. The magnetic-field dependences of the critical currents, lower critical fields and the flux penetration are briefly discussed.