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.