Ferromagnetic ordering in ThSi 2 type CeAu 0.28Ge 1.72

Abstract

The compound CeAu 0.28Ge 1.72 crystallizes in the ThSi 2 structure type in the tetragonal space group I4 1/ 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 50 K. The compound orders ferromagnetically at ∼8 K with estimated magnetic moment of 2.48 μ B/Ce. The ferromagnetic ordering is confirmed by the heat capacity data which show a rise at ∼8 K. The electronic specific heat coefficient ( γ) value obtained from the paramagnetic temperature range 15–25 K is∼124(5) mJ/ mol K 2. The entropy change due to the ferromagnetic transition is ∼4.2 J/mol K which is appreciably reduced compared to the value of R ln(2) expected for a crystal-field-split doublet ground state and/or Kondo exchange interactions.