Investigation of single, sharp line signals in modulated microwave absorption spectra at low magnetic fields in YBa2Cu3O7–δ single crystal

Abstract

Low-field microwave absorption (LFMA) in a YBa₂Cu₃O_7–δ single crystal is reported. Two single, sharp lines are detected. The microwave power dependence of both signals is very similar to that of periodic line patterns observed earlier in the LFMA spectra of YBaCuO single crystals. We conclude that the two different types of LFMA spectra possess a common origin. The microwave power thresholds measured in our crystal are much higher than the threshold determined in other crystals. Some magnetic field hysteresis effects are also observed.