A Heavy-Fermion Zn-deficient CaBe2Ge2-Type Phase with Rare Ce-based Ferromagnetism and Large Magnetoresistance

TL;DR

This study reports a new CeZn2-dGe2 compound with a defect CaBe2Ge2 structure, exhibiting rare Ce-based ferromagnetism, large magnetoresistance, and heavy fermion behavior, making it a promising platform for studying complex electronic states.

Contribution

It introduces a previously unknown CeZn2-dGe2 phase with unique magnetic and electronic properties, expanding the understanding of heavy fermion and ferromagnetic materials.

Findings

CeZn2-dGe2 exhibits ferromagnetism at 6.6 K.

Large positive magnetoresistance of ~32% below 10 K.

Strongly correlated electrons indicated by Kadowaki-Woods ratio.

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.