Thermodynamics and magnetism in U1−<i>x</i>Th<i>x</i>Be13−<i>y</i>By

Abstract

We report specific heat and μSR measurements on Th (x =0.019) and/or B (y=0.03) substituted UBe13. The specific heat data show that either Th or B substitution reduces the Kondo temperature TK and increases the entropy at the superconducting transition by almost 20%, indicating an enhanced density of states. However, whereas μSR shows clear evidence for magnetic correlations for Th substitutions (0.019&amp;lt;x&amp;lt;0.043), no magnetism is observed for B substitutions. The enhanced specific heat jump in the B-substituted material is associated with a change in the superconducting properties as TK is reduced.