Revisiting the properties of the heavy-fermion superconductor UBe₁₃ via polycrystalline samples

The unconventional superconducting behavior of UBe₁₃ is still an active research topic [1, 2], despite it being one of the first reported heavy-fermion superconductors [3]. Recently it was shown [4] that the physical properties of single crystals grown from Al flux – a method that was available from the very outset [3] – are significantly affected by Al incorporation into the lattice even though the amount is rather small (< 1-2 at. %). This contribution will present an alternative way in which polycrystalline samples can be used to gain insight into the intrinsic properties of UBe₁₃. By concentrating on polycrystalline samples, we completely avoid the problem of Al inclusions and thus examine the effect of the inherent crystallographic defects (both at the atomic- and the microscale) in UBe₁₃ on the critical temperature T_c, the Sommerfeld coefficient γ, and the size of the specific heat anomaly.

[1] G.R. Stewart, J. Low. Temp. Phys. 195, 1 (2019).
[2] Y. Shimizu, et al. , Phys. Rev. Lett. 122, 067001 (2019)
[3] H. R. Ott, et al., Phys. Rev. Lett. 50, 1595 (1983).
[4] A. Amon, et al., Sci. Rep. 8, 10654 (2018).