AN ANISOTROPIC MICROWAVE ABSORPTION IN YBa 2 Cu 3 O 7-δ THIN FILM

A very strong nonresonant low-field signal can be detected near and below zero resistance phase transition temperature T_c by either electron spin resonance (ESR) or nuclear magnetic resonance (NMR)in almost all systems of high T_c superconductive oxides. The essence of this phenomenon is that there is some loss absorption of electromagnetic radiant in the sample when it is in the normal state; and the absorption decreases obviously when it is in the superconducting state, but the absorption increases when the sample is in magnetic field, especially when the applied field H is greater than the superconducting lower