Magnetic susceptibility of the normal-superconducting transition in   high-purity single-crystal alpha-uranium
  We report complex ac magnetic susceptibility measurements of a superconducting transition in very high-quality single-crystal alpha-uranium using microfabricated coplanar magnetometers. We identify an onset of superconductivity at T~0.7 K in both the real and imaginary components of the susceptibility which is confirmed by resistivity data. A superconducting volume fraction argument, based on a comparison with a calibration YBCO sample, indicates that the superconductivity in these samples may be filamentary. Our data also demonstrate the sensitivity of the coplanar micro-magnetometers, which are ideally suited to measurements in pulsed magnetic fields exceeding 100 T. 
J.L. O'Brien, A.R. Hamilton, R.G. Clark, C.H. Mielke, J.L. Smith, J.C.   Cooley, D.G. Rickel, R.P. Starrett, D.J. Reilly, N....