Inversion symmetry breaking superconductors: Re$_3$W and Re$_3$Mo

Superconductors that break inversion symmetry and have strong spin-orbit coupling are theoretically predicted to have many anomalous properties, including the development of a two-gap structure in the superconducting density of states. One recent example of such a material is CePt3Si, which has attracted much recent attention. We have begun to examine two other materials that meet these criteria, Re3Mo and Re3W, both of which crystallize in the $\alpha $-Mn structure that breaks inversion symmetry. Here we present X-ray diffraction, magnetization, resistivity, and specific heat data on both Re3Mo and Re3W. Characteristic parameters of the superconductivity are extracted, and the data are closely examined for any deviation from ordinary BCS behavior. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725.