Coercivity Enhancement in V$_{2}$O$_{3}$/Ni Bilayers

We studied the temperature dependence of the coercivity and magnetization of V$_{2}$O$_{3}$/Ni bilayers. When the V$_{2}$O$_{3}$ is in the middle of the metal to insulator transition, we observe a maximum enhancement of the coercivity and a decrease of the magnetization. The maximum value of the coercivity shows a 300{\%} increment compared to the room temperature value. The decrease of the magnetization indicates magnetic domain formation. We propose a model in which the inhomogeneous V$_{2}$O$_{3}$ phase transition induces nanoscale stress and disorder in the Ni film. The local stress anisotropy and disorder break the Ni film into magnetic domains and pin the domain walls in Ni. The model is supported by micromagnetic simulations and shows that magnetic properties of ferromagnetic films are strongly affected by the proximity to materials that undergo inhomogeneous phase transition at nanoscale.