Magnetic phase transitions in thin films of the near-itinerant spinel CoV₂O₄

Spinel vanadates are frustrated antiferromagnets, of interest due to the orbital physics that can be tuned via structural perturbations. The V-V distance determines proximity of the system to a localized-itinerant crossover, with CoV₂O₄ the closest known material to this transition. Previously, we have shown that CoV₂O₄ films are orthorhombic rather than cubic. The films undergo a spin canting/orbital order transition at low temperature, i.e., they show very different magnetic properties compared to bulk [1]. Based on recent magnetization measurements as a function of temperature we find signatures of three distinct magnetic transitions in the films. We investigate temperature, field, and film thickness dependence of these transitions, and we discuss the roles that single-ion anisotropy and shape anisotropy play.
[1] C. J. Thompson, D. Reig-i- Plessis, L. Kish, A. A. Aczel, B. Zhang, E. Karapetrova, G. J. MacDougall, and C. Beekman, arXiv:1805.01520 [cond-mat.str-el] (accepted for publication with Physical Review Materials)