A Heavy Fermion Zn-Deficient CaBe2Ge2-Type Phase with Rare Ce-Based Ferromagnetism and Large Magnetoresistance

Abstract

We report on the hitherto unknown compound CeZn2-dGe2 (d approx 0.41). We find this compound to crystallize in a defect version of the well-known CaBe2Ge2 structure type. The phase forms in a Zn/In flux and with Zn-deficiency on one of its crystallographic sites. We find the compound to display uncommon localized Ce-based (4f1) ferromagnetism with a Tc = 6.6 K, a large positive magnetoresistance reaching an MR of approximately 32 % below $T$ = 10 K, and strongly correlated electrons, as evidenced by a Kadowaki-Woods ratio A/gamma^2 close to known heavy fermion compounds. The here discovered material is therefore a promising model platform for the investigation of these entangled interacting and potentially competing electronic states paired with complex crystal chemistry.