О магнитометрическом определении концентрации радиационных дефектов в сверхпроводящей пленке GdBa-=SUB=-2-=/SUB=-Cu-=SUB=-3-=/SUB=-O-=SUB=-7-x-=/SUB=-

An express magnetometric technique is proposed, which makes it possible to determine the inhomogeneity of the change in the superconducting properties of a thin superconductor layer due to radiation exposure. A numerical simulation of this technique is carried out using the example of a superconducting GdBa2Cu3O7-x layer irradiated with hydrogen and helium ions. The profile of the concentration of radiation defects was calculated using the SRIM software package. The calculation of the density distribution of superconducting currents induced by an external magnetic field was carried out within the framework of the critical state model. Model calculations have shown the effectiveness of the proposed method.

SOME PECULIARITIES OF USING OF DIELECTRIC RESONATORS IN MICROWAVE SURFACE IMPEDANCE MEASUREMENTS

A simple equivalent circuit of the dielectric resonator technique, using for measurement of the surface resistance of the samples of non-standard dimensions, was considered and analyzed. It was shown that the coefficient (the geometry factor) relating the surface resistance of the sample to the quality factor may be different in the cases when the inductive resistance (caused by the external inductance) of the sample exceeds significantly its active resistance and when these resistances are of the same order. It was shown too, that an anomaly in the RS versus T dependence (i.e., a decreasing of the surface resistance with increase of the temperature) is possible in double layer structures with thin superconductor and metal films.