Specific heat and magnetization studies of the superconducting mixed state of UBe₁₃

Low-temperature specific heat and static dc magnetizetion measurements have been performed for the superconducting state of the heavy-fermion compound UBe₁₃. The superconducting phase diagram B_c2-T (B || [110]) has been obtained by our specific heat and magnetization measurements. From the slope of the upper critical field and specific heat jumps at superconducting transition temperatures in magnetic fields, we have also obtained a temperature dependence of Ginzburg-Landau parameter κ₂ along [110]. It has been revealed that κ₂ decreases with decreasing temperature down to 0.5 K, which indicates that a paramagnetic effect may be present at least down to 0.5 K for [110].