Magnetic Properties of Vanadium Oxide/Ferromagnetic hybrid composites

The temperature dependence of the coercivity and magnetization of vanadium oxide/ferromagnet composite powders was studied. The vanadium oxides VO2 and V2O3 exhibit a well-known temperature induced Structural Phase Transition (SPT). When incorporated in ferromagnetic/vanadium oxide hybrid systems, the SPT of the oxide induces an inverse magnetoelastic effect that strongly modifies the coercivity and magnetization of ferromagnetic films (1) and powder composites (2). In this work different combinations of vanadium oxide and ferromagnetic powders were ball-milled and sintered to form a powder composite. Magnetic properties were measured using a Vibrating Sample Magnetometer. The milling and sintering conditions allow tuning of the magnetic properties. For some sintering conditions, irreversibility in the coercivity is observed after the first cycle of the thermally induced phase transformation. These results indicate that properties of vanadium oxide/ferromagnet composite hybrid powders are strongly affected by the strain induced SPT and that it is possible to control the magnetic properties by tuning the sintering conditions. 1. J. de la Venta el al Applied Physics Letters 104, 062410 (2014) 2. C. Urban et al 109, 112401 (2016)