Large resistivity change and phase transition in the antiferromagnetic semiconductors LiMnAs and LaOMnAs

Abstract

Antiferromagnetic semiconductors are new alternative materials for spintronic applications and spin valves. In this work, we report a detailed investigation of two antiferromagnetic semiconductors $A$MnAs ($A=\mathrm{Li}$, LaO), which are isostructural to the well-known LiFeAs and LaOFeAs superconductors. Here we present a comparison between the structural, magnetic, and electronic properties of LiMnAs, LaOMnAs, and related materials. Interestingly, both LiMnAs and LaOMnAs show a variation in resistivity with more than five orders of magnitude, making them particularly suitable for use in future electronic devices. Neutron and x-ray diffraction measurements on LiMnAs show a magnetic phase transition corresponding to the N\'eel temperature of 373.8 K, and a structural transition from the tetragonal to the cubic phase at 768 K. These experimental results are supported by density functional theory calculations.