Microwave surface impedance of a Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8/ single crystal and derivation of rho /sub c/(T,B)

Microwave surface impedance measurements are reported for a high-quality Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8/ single crystals platelet over a wide range of temperatures in DC fields parallel and perpendicular to the ab-planes. A large field and frequency dependent peak is observed in the loss component below T/sub c/. Because of the giant anisotropy of resistivities parallel and perpendicular to the ab-planes, microwave penetration from the thin edges of the platelet is as important as that across the major faces in the normal state and becomes the dominant source of microwave loss in the superconducting state. To analyze the measurements, a theoretical expression has been derived for microwave absorption in an anisotropic long rectangular slab. The observed temperature and field dependences of microwave losses for the superconducting and normal states are simulated using model temperature and field-dependent conductivities. Microwave losses are used to derive the linear, thermally activated resistivity in the c-direction.<
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