Properties of high-Tc superconductors at RF and microwaves : experimental data and some model notions

Abstract
In this paper we try to summarize experimental data on high-Tc superconductors (HTSC) behaviour in RF and microwave electromagnetic field accumulated to this day. The main emphasis is made on Y-Ba-Cu-O material for which the most complete information is available. We show that it is intergranular junctions that play an essential role in the formation of electromagnetic properties of the ceramics with p ≅ 10-4 Ω x m. We suggest a model of the HTSC single crystal where the charge carriers are tunneling « biholes » obeying the Bose statistics and are localized within a unit cell. This model can describe field penetration depth and critical current density as a functions of temperature as well as temperature and frequency dependence of surface resistance. The presence of normal conducting regions can be a course of HTSC single crystal residual resistance. A close agreement between experimental data and model calculations is demonstrated