UBe13 and U1−xThxBe13: Unconventional Superconductors

UBe13 was the second discovered heavy fermion superconductor, and numerous pieces of evidence exist that imply that it is an unconventional (non-BCS s-wave) superconductor. Exhibiting even more signs of unconventional superconductivity, Th-doped UBe13 is perhaps the most puzzling of any of the unconventional superconductors. This review considers both the parent, undoped compound as well as the more interesting U1−xThxBe13. After summarizing the rather thorough characterization—which because of the interest in these compounds, has continued from their discovery in 1983 and 1984 to date—these properties are compared with a recent ‘template’ for determining whether a superconductor is unconventional. Finally, further experiments are suggested.