LOW-FREQUENCY NOISE OF THE MODULATED MICROWAVE-ABSORPTION IN THE SUPERCONDUCTING CRYSTAL YBA2CU3O6+X

Low-frequency noise of the modulated microwave absorption (MMA) in the weak magnetic fields was studied in the superconducting crystal YBa2C u3O6+x. The temperature dependence of the MMA consists of three distin ct regions with the phase transition temperatures T-c = 93, 65 and 30 K. The temperature dependence of the noise power exhibits the oscillat ing shape with the period of oscillation about 10 K. The increase of t he noise is connected with the appearance infralow and low frequencies in the noise spectrum. The noise power depends on the modulation ampl itude unlinearly. The sharp peak of oscillating noise arises near T-c, when a modulation amplitude increased. This peak associates with the same of MMA.