Temperature dependence of the microwave surface impedance measured on different kinds of MgB${}_2$ samples

A. A. Zhukov, L. F. Cohen, A. Purnell +11

In this paper we present the results of measurements of the microwave surface impedance of a powder sample and two films of MgB${}_2$. One film has $T_c=30$ K and is not textured, th…