Reduction of critical temperatures in pure and thoriated UBe13 by columnar defects

We investigate the influence of columnar defects on the superconducting transition temperatures of pure and thoriated UBe13. The defects cause all the transitions to widen and to drop slightly in temperature. Quantitatively, the single UBe13 transition resembles the lower transition in a sample with 3% thorium more closely than the upper thoriated transition.