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

Compensated ferrimagnets show no net magnetization like antiferromagnets, 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 of the noncollinear triangular 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 mu(B) moments of Mn on 3c sites of the (111) kagome planes tilt about 20 degrees out-of-plane in Mn4N and are easily influenced by the substitutions on 1a sites, leading to an efficiency of compensation in Mn(4-x)Z(x)N that increases gradually from group 11 (Cu, Ag) to group 14 (Ge, Sn) with increasing number of valence 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 analyzed by constrained density functional theory are determined by Z, orbital hybridization, charge transfer and the tilt angle. The Ga compound with compensation at room temperature for x approximate to 0.26 is recommended for high-frequency spintronic applications. (C) 2022 The Author(s). Published by Elsevier Ltd on behalf of Acta Materialia Inc.

Automated summary

This study investigates the compensation of the noncollinear triangular ferrimagnetic spin structure of Mn4N using metallic substitutions. The efficiency of compensation increases with the number of valence electrons of the substitution elements. The Ga compound with compensation at room temperature for x≈0.26 is recommended for high-frequency spintronic applications.