Ferromagnetic phase of spinel compound MgV$_2$O$_4$ and its spintronics properties

TL;DR

This study uses first-principles calculations to explore the ferromagnetic phase of MgV₂O₄, revealing flat bands near the Fermi level and potential for spintronics applications through half-metallicity and phase transition control.

Contribution

It demonstrates the existence of a ferromagnetic phase in MgV₂O₄ with flat bands and large anomalous Hall effect, and proposes methods to stabilize this phase for spintronics.

Findings

Flat bands near Fermi level in FM phase

Large anomalous Hall effect (~670 S/cm)

Potential for phase transition via doping

Abstract

Spinel compound, MgV$_2$O$_4$, known as a highly frustrated magnet has been extensively studied both experimentally and theoretically for its exotic quantum magnetic states. However, due to its intrinsic insulating nature in its antiferromagnetic (AFM) ground state, its realistic applications in spintronics are quite limited. Here, based on first-principles calculations, we examine the ferromagnetic (FM) phase of MgV$_2$O$_4$, which was found to host three-dimensional flat band (FB) right near the Fermi level, consequently yielding a large anomalous Hall effect (AHE, $\sigma \approx 670\,\Omega^{-1}\cdot cm^{-1}$). Our calculations suggest that the half-metallicity feature of MgV$_2$O$_4$ is preserved even after interfacing with MgO due to the excellent lattice matching, which could be a promising spin filtering material for spintronics applications. Lastly, we explore experimental feasibility of stabilizing this FM phase through strain and doping engineering. Our study suggests that experimentally accessible amount of hole doping might induce a AFM-FM phase transition.