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

EuZn$_2$P$_2$ was reported to be an insulating antiferromagnet with\n$T_\\mathrm{N}$ of 23.5 K. In this study, single crystals of EuZn$_2$P$_2$\nexhibiting metallic behavior and a ferromagnetic order of 72 K ($T_\\mathrm{C}$)\nare successfully synthesized via a salt flux method. The presence of hole\ncarriers induced by the Eu vacancies in the lattice is found to be crucial for\nthe drastic changes in magnetism and electrical transport. The carriers mediate\nthe interlayer ferromagnetic interaction, and the coupling strength is directly\nrelated to $T_\\mathrm{C}$, as evidenced by the linear dependence of\n$T_\\mathrm{C}$ and the fitted Curie-Weiss temperatures on the Eu-layer\ndistances for ferromagnetic Eu$M_2X_2$ ($M$ = Zn, Cd; $X$ = P, As). The\nferromagnetic EuZn$_2$P$_2$ shows conspicuous negative magnetoresistance (MR)\nnear $T_\\mathrm{C}$, owing to strong magnetic scattering. The MR behavior is\nconsistent with the Majumdar-Littlewood model, indicating that the MR can be\nenhanced by decreasing the carrier density. Our findings suggest that\nEu$M_2X_2$ has highly tunable magnetism and charge transport, making it a\npromising material family for potential applications in spintronics.\n