Magnetic and Mössbauer studies on rare-earth-containing Heusler alloysPd2RSn (R=Tb–Yb)

Abstract

Magnetic susceptibility and ${}_{}{}^{119}{}_{}{}^{}\mathrm{Sn}$ Mössbauer studies have been carried out on a new series of rare-earth-containing Heusler alloys having the formula ${\mathrm{Pd}}_2$RSn (R=Tb–Yb). The Tm and Yb compounds in this series along with Lu, Sc, and Y compounds are superconducting. The magnetic susceptibility of ${\mathrm{Pd}}_2$TmSn and ${\mathrm{Pd}}_2$YbSn deviates from the Curie-Weiss behavior at low temperatures indicating that crystalline electric field effects are appreciable. Analysis of the magnetic susceptibility data in terms of crystalline electric fields shows that the ground state of the ${\mathrm{Tm}}^{3+}$ ion is nonmagnetic which, therefore, does not affect the superconducting state. The susceptibility of ${\mathrm{Yb}}^{3+}$ ions at low temperatures is also reduced from the free-ion value due to the crystalline electric field interaction. The Tb- and Dy-containing compounds order antiferromagnetically with Néel temperatures of 9 and 15 K, respectively, while Er- and Ho-containing compounds are paramagnetic down to 1.4 K. The hyperfine field at the Sn site in ${\mathrm{Pd}}_2$TbSn is about 50 kOe but is only about 10 kOe in ${\mathrm{Pd}}_2$DySn at 4.2 K.