Ferromagnetic ordering in ThSi₂ type CeAu_0.28Ge_1.72

Abstract

The compound CeAu_0.28Ge_1.72 crystallizes in the ThSi₂ structure type in the tetragonal space group I4₁/amd with lattice parameters a=b=4.2415(6)Å c=14.640(3)Å. CeAu_0.28Ge_1.72 is a polar intermetallic compound having a three-dimensional Ge/Au polyanion sub-network filled with Ce atoms. The magnetic susceptibility data show Curie-Weiss law behavior above 50K. The compound orders ferromagnetically at ∼8K with estimated magnetic moment of 2.48μ_B/Ce. The ferromagnetic ordering is confirmed by the heat capacity data which show a rise at ∼8K. The electronic specific heat coefficient (γ) value obtained from the paramagnetic temperature range 15-25K is ∼124(5)mJ/molK². The entropy change due to the ferromagnetic transition is ∼4.2J/molK which is appreciably reduced compared to the value of Rln(2) expected for a crystal-field-split doublet ground state and/or Kondo exchange interactions.