EFFECTIVE-MEDIUM THEORY FOR GRANULAR HIGH-TC SUPERCONDUCTORS ELECTROMAGNETIC PROPERTIES IN THE MICROWAVE REGION

The authors extend to finite frequencies their recently developed effective-medium theory (EMT) for granular high-Tc superconductors (HTS). Here they present results for the electromagnetic properties in the microwave region, which is of potential significance for early commercial applications of HTS materials. Most of their discussions centre on generalisations of classical Mie scattering theory to spherical superconductor grains. However, there are important corrections to previous works on EMT at finite frequencies by Stroud and Pan (1978) and also Mahan (1988), which they discuss. Some illustrative numerical results are presented, deferring lengthy numerical computations and comparisons with experiments, to be published elsewhere.