Magnetic properties of hematite revealed by an ab initio parameterized spin model

Abstract

Hematite is a canted antiferromagnetic insulator, promising for applications in spintronics. Here, we present ab initio calculations of the tensorial exchange interactions of hematite and use them to understand its magnetic properties by parameterizing a semiclassical Heisenberg spin model. Using atomistic spin dynamics simulations, we calculate the equilibrium properties and phase transitions of hematite, most notably the Morin transition. The computed isotropic and Dzyaloshinskii--Moriya interactions result in a Néel temperature and weak ferromagnetic canting angle that are in good agreement with experimental measurements. Our simulations show how dipole-dipole interactions act in a delicate balance with first and higher-order on-site anisotropies to determine the material's magnetic phase. Comparison with spin-Hall magnetoresistance measurements on a hematite single-crystal reveals deviations of the critical behavior at low temperatures. Based on a mean-field model, we argue that these differences result from the quantum nature of the fluctuations that drive the phase transitions.

arXiv comment11 pages, 10 figures

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Cited by in corpus (7)

• Antiferromagnetic insulatronics: spintronics in insulating 3d metal oxides with antiferromagnetic coupling
• Altermagnetic splitting of magnons in hematite ($\alpha$-Fe${}_2$O${}_3$)
• Revealing the Altermagnetism in Hematite via XMCD Imaging and Anomalous Hall Electrical Transport
• Quantum Sensing of Antiferromagnetic Magnon Two-Mode Squeezed Vacuum
• Tunable Enhancement of Magnetization Dynamics by Crystal Cut at Interface Exchange Coupled $\alpha$-Fe${}_2$O${}_3$/NiFe Heterostructures
• Squeezing and quantum control of antiferromagnetic magnon pseudospin
• Quantum fluctuations determine the spin-flop transition in hematite