Rare-earth-free noncollinear metallic ferrimagnets Mn4-xZxN with compensation at room temperature

TL;DR

This study explores how metallic substitutions in Mn4N can induce room-temperature magnetic compensation, creating rare-earth-free ferrimagnets with potential high-frequency spintronic applications.

Contribution

It demonstrates that specific metallic substitutions in Mn4N can achieve room-temperature magnetic compensation, advancing the development of rare-earth-free ferrimagnets.

Findings

Compensation achieved in Mn4-xZxN with Z = Cu, Ag, Ge, Sn.

Compensation efficiency increases from group 11 to group 14 elements.

Ga compound with x=0.26 shows room-temperature compensation.

Abstract

Compensated ferrimagnets, like antiferromagnets, show no net magnetization but their transport and magneto-optic properties resemble those of ferromagnets, thereby creating opportunities for applications in high-frequency spintronics and low-energy loss communications. Here we study the modification the noncollinear ferrimagnetic spin structure of Mn4N by a variety of metallic substitutions Z (Z = Cu - Ge and Ag - Sn) to achieve compensation at room temperature. The noncollinear frustrated 2.35 Bohr magneton moments of Mn on 3c sites of the (111) kagome planes tilt about 20 degree out-of-plane in Mn4N and are easily influenced by the substitutions on 1a sites, leading to different efficiency of compensation in Mn4-xZxN that increases gradually from group 11 (Cu, Ag) to group 14 (Ge, Sn) with increasing number of valance electrons. Elements from the 5th period are more efficient for compensation than those from the 4th period due to lattice expansion. The manganese site moments are determined by Z, orbital hybridization, charge transfer and the tilt angle, analyzed by constrained density functional theory. The Ga compound with compensation at room temperature for x = 0.26 is recommended for high-frequency spintronic applications.