Origin and tuning of room temperature ferromagnetism and ferroelectricity in double perovskite Y2NiMnO6 nanostructured thin films

This work reports successful fabrication of double perovskite Y2NiMnO6 nanostructured thin films by pulsed laser deposition technique in oxygen and argon gas atmospheres. The Y2NiMnO6 nanostructured thin films exhibit unexpected above room temperature ferromagnetism and ferroelectricity, indicating the coexistence of more than one ferroic interaction in nanostructured Y2NiMnO6. It is found that the dimension of the nanostructures present in the thin films controls both the ferroelectric and magnetic order of Y2NiMnO6 thin films. Studies indicate that the room temperature ferromagnetism and ferroelectricity have similar origin and can be ascribed to the unsaturated surface spins and surface charge polarization, respectively, associated with the surface of the tiny nanostructures, which constitute the whole thin films. Magnetic force microscopy and piezoelectric force microscopy studies confirm the coexistence of the ferromagnetic and ferroelectric domains in the nanostructured films, respectively, at room temperature. This study demonstrates that tailoring of morphology of the nanostructures provides ample opportunity to tune the inherent ferroelectric and magnetic orders of the Y2NiMnO6 nanostructured thin films.