Carrier-induced transition from antiferromagnetic insulator to ferromagnetic metal in the layered phosphide EuZn2P2

EuZn₂P₂ was reported to be an insulating antiferromagnet with TN of 23.5 K. In this study, single crystals of EuZn₂P₂ exhibiting metallic behavior and a ferromagnetic order of 72 K (TC) are successfully synthesized via a salt flux method. The presence of hole carriers induced by the Eu vacancies in the lattice is found to be crucial for the drastic changes in magnetism and electrical transport. The carriers mediate the interlayer ferromagnetic interaction, and the coupling strength is directly related to TC, as evidenced by the linear dependence of TC and the fitted Curie-Weiss temperatures on the Eu-layer distances for ferromagnetic EuM₂X₂ (M = Zn, Cd; X = P, As). The ferromagnetic EuZn₂P₂ shows conspicuous negative magnetoresistance (MR) near TC, owing to strong magnetic scattering. The MR behavior is consistent with the Majumdar-Littlewood model, indicating that the MR can be enhanced by decreasing the carrier density. Our findings suggest that EuM₂X₂ has highly tunable magnetism and charge transport, making it a promising material family for potential applications in spintronics.