Multiferroic VHfO₄ with Strain-Tunable Magnetism

Abstract

The coexistence of ferroelectricity and magnetism in a single-phase oxide is rare because the electronic requirements for these two orders are often incompatible. Here, using first-principles calculations and parallel-tempering Monte Carlo simulations, we propose stoichiometric VHfO₄ as a hafnia-derived multiferroic that overcomes this constraint through ordered cation design rather than dilute magnetic doping. We found that VHfO₄ adopts a symmetry-lowered polar Pc structure derived from the ferroelectric Pca2₁ phase, with layered V/Hf ordering, local dynamical stability, and switchable ferroelectricity with a large spontaneous polarization. The ordered V sublattice introduces competing exchange interactions that favor an antiferromagnetic ground state at zero strain. Epitaxial strain further drives transitions into additional phases, including a noncollinear spiral-like state and a predominantly in-plane antiferromagnetic state. We also find that out-of-plane lattice distortions along the polar axis strongly modify the exchange interactions and magnetic phase stability, indicating a strain-mediated pathway for electric-field control of magnetism. These results establish VHfO₄ as a promising artificial-superlattice candidate for exploring multiferroicity and magnetoelectric coupling in hafnia-based oxides.

Keywords

multiferroic / strain-tunable magnetism / non-perovskite ferroelectric / first principle calculations

RIGHTS & PERMISSIONS

Higher Education Press 2026

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