Magnetic Field Dependence of the Surface Impedance of Superconducting Tin at 3 kMc/sec

Abstract

The real and imaginary parts of the surface impedance of superconducting tin have been measured as a function of applied magnetic field by use of a microwave resonator at a frequency of 3 kMc/sec. For most crystalline orientations, the surface resistance and rectance of pure tin were found to decrease with field above 0.85 of the critical temperature but to increase with field at lower temperatures. The negative field dependence, which occurs near the critical temperature, becomes positive when the tin is alloyed with a few tenths of a percent of indium. These results are compared with the Dresselhaus theory, and certain discrepancies are discussed.