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.

在薄膜体系中复刻块体氧化物的本征性能，对器件应用至关重要。本研究系统探究了氧分压与缓冲层对双钙钛矿Y₂NiMnO₆（double perovskite Y₂NiMnO₆，缩写为YNMO）薄膜的调控作用。研究发现，提升氧分压可促进YNMO薄膜的晶格弛豫，降低Mn³+离子占比，并增强其磁化强度。高氧分压条件下制备的YNMO薄膜，其面外晶格常数可被调控至与块体样品近乎匹配。此外，引入CaTiO₃缓冲层有助于Mn离子氧化为Mn⁴+；该缓冲层可显著调控YNMO薄膜的自旋状态，但对其晶格结构几乎无影响。通过氧分压与CaTiO₃缓冲层的协同调控，所制备的YNMO薄膜在晶格结构、元素组分与磁化性能上均与块体样品近乎一致。