Characteristic features of the temperature dependence of the surface impedance in polycrystalline MgB${}_2$ samples

Yu. A. Nefyodov, M. R. Trunin, A. F. Shevchun +5

The real $R_s(T)$ and imaginary $X_s(T)$ parts of the surface impedance $Z_s(T)=R_s(T)+i{X}_s(T)$ in polycrystalline MgB${}_2$ samples of different density with the critical temperatur…