Field-induced reentrant superconductivity in the Heusler alloy system ${\mathrm{Pd}}_2$${\mathrm{Y}}_{1\mathrm{-}\mathrm{x}}$${\mathrm{Dy}}_{\mathrm{x}}$Sn

The ternary compound ${\mathrm{Pd}}_2$YSn crystallizing in the cubic Heusler (L$2_1$) structure is superconducting with a superconducting transition temperature ($T_c$) of 4.55 K. The superconducting and magnetic phase diagram of the pseudoternary system ${\mathrm{Pd}}_2$ ${\mathrm{Y}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Dy}}_{\mathrm{x}}$Sn (x=0–1) has been investigated. The superconducting $T_c$ of ${\mathrm{Pd}}_2$YSn decreases with the replacement of Y by Dy and superconductivity is completely suppressed at a critical concentration of Dy corresponding to x∼0.35. The samples with x≥0.5 are antiferromagnetically ordered with Néel temperatures ranging from 5 K for x=0.5–15 K for x=1.0 (${\mathrm{Pd}}_2$DySn). The superconducting samples with x>0 show reentrant behavior under external applied fields. The temperature dependence of the upper critical field in ${\mathrm{Pd}}_2$ ${\mathrm{Y}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Dy}}_{\mathrm{x}}$Sn (x=0.0, 0.1, and 0.15) has been measured and is analyzed in terms of the Werthamer-Helfand-Hohenberg theory including the pair-breaking effects due to paramagnetic rare-earth ions.