Microwave performance of high-density bulk MgB2

A. T. FINDIKOGLU; A. SERQUIS; L. CIVALE; X. Z. LIAO; Y. T. ZHU; M. E. HAWLEY; V. F. NESTERENKO; Y. GU

APPLIED PHYSICS LETTERS

American Institute of Physics

Año: 2003 vol. 82 p. 108 - 110

0003-6951

We have performed microwave measurements on superconducting hot-isostatically pressed (HIPed) bulk MgB2 using a parallel-plate resonator technique. The high density and strength of the HIPed material allowed preparation of samples with mirror-like surfaces for microwave measurements. The microwave effective surface resistance Rs decreased by about 40% at 20 K when the root-mean-square surface roughness was reduced from 220 to 110 nm through surface polishing and ion milling. The Rs was independent of surface microwave magnetic field at least up to 4 Oe and below 30 K. We attribute this behavior, and the overall low Rs (0.8 mOhm at 10 GHz and 20 K), to the high density of our samples and the absence of weak links between grains.