Manipulating the structural and magnetic properties of double perovskite Y2NiMnO6 thin films by oxygen pressure and buffer layer

Replicating the properties of a bulk oxide in its film counterpart is critical for device applications. In this work, the effects of oxygen pressure and buffer layer on double perovskite Y2NiMnO6 (YNMO) thin films have been studied carefully. The increase in oxygen pressure is found to contribute to the lattice relaxation, reduction of Mn3+ ions, and enhancement of magnetization of YNMO films. The out-of-plane lattice constant of the YNMO film at high oxygen pressure can be tuned to nearly match that of the bulk. Moreover, the insertion of a CaTiO3 buffer layer is beneficial for the oxidization of Mn4+ ions. It affects the spin state of YNMO films significantly, while it has little influence on the lattice structure. With co-action of oxygen pressure and the CaTiO3 buffer layer, the lattice structure, element composition, and magnetization of the obtained YNMO films are almost comparable to those of the bulk.