Two-Pulse and Stimulated Echoes in Yttrium and Bismuth Based HTS C Powders
Yu. M. Tsipenyuk
Chinese Journal of Physics
|Volume or Term/Year and Month of Publication||
34卷2S期（1996 / 04 / 01）
484 - 488
Experimental data on a two-pulse and a stimulated echoes in a superconducting YBaCuO and BiSrCaCuO powders in a static magnetic field at a frequency～20 MHz' are presented. The field, filling helium gas pressure and temperature dependence of the echo intensity and relaxation time were measured. A stimulated echo has been even detected some hours after the removal of exciting pulses (the memory effect). The echoes are practically disappeared at temperatures 50 K for yttrium powder and at 30 K in the case of Bi-powder. Experimental results are in a qualitative agreement with a supposition that the phase coherence arises due to the movement of lattice imperfections by vortex lines.