Phenomenological model for the anomalous peaks in the microwave surface resistance of high temperature superconductors

The paper presents a simple model to describe the observed anomalous peaks below transition temperature in the microwave surface resistance in single crystal and bulk samples of high temperature superconductors. The peaks observed in YBCO single crystals and BPSCCO bulk samples are due to the suppression in the quasi-particle scattering rate, which are affected by the presence of impurities in the samples. The two key parameters of the present phenomenological model are the power law factor 'gamma' of extended two fluid model and the residual to intrinsic resistivity ratio 'r' deciding the impurity level in the sample. These two empirical parameters of the model are able to explain the temperature dependent amplitude and position of the surface resistance peaks. Results of the theoretical model are fitted with the published experimental data on ordered YBCO single crystal to disordered bulk BPSCCO bulk samples. (C) 2002 Elsevier Science B.V. All rights reserved.