Magnesium diboride (MgB2) is attractive for RF cavity application for particle accelerators because it might not show an increase of RF surface losses at high magnetic surface fields, a phenomenon that has prevented high-Tc superconducting materials such as YBCO from being used for this application. We have measured the RF surface resistance (Rs) at 21 GHz of a MgB2 sample fabricated using Hot Isostatic Press (HIP) at 200 MPa and 1000 C. The results show that polishing with 0.1-micron diamond lapping film followed by a 1500-psi DI water rinse in a clean room reduced the Rs by a factor of 6.2 at 15 K and it is the lowest compared to other published data. The Rs data near the lowest temperature (~13 K) scatter between 0.6 and 1.3 mOhm. The penetration depth and energy gap were estimated to be 263 nm and 1.9-2.7, respectively, for the polished surface.
@article{arxiv.cond-mat/0310213,
title = {RF Surface Resistance of a HIPped MgB2 Sample at 21 GHz},
author = {T. Tajima and F. L. Krawczyk and J. Liu and D. C. Nguyen and D. L. Schrage and A. Serquis and A. H. Shapiro and V. F. Nesterenko and Y. Gu},
journal= {arXiv preprint arXiv:cond-mat/0310213},
year = {2007}
}