With the development of electronic information technology, the miniaturization of lightweight devices and their integration have increased the requirements for materials, and two-dimensional composite multiferroic materials have become a major research hotspot in recent years. However, it is difficult for traditional solid multiferroic material to directly switch the magnetic/polarization direction under the action of an applied electric/magnetic field, limiting the improvement of the magnetoelectric coupling coefficient. In this study, a series of BiFeO (BFO)/CoFeO (CFO) composite film multiferroic materials were prepared by changing the annealing routes and annealing atmosphere, the microstructure, ferroelectric properties, dielectric properties, photovoltaic properties, magnetic properties, and magnetoelectric coupling properties of composite films were routeatically studied. The results showed that under the slow annealing route, the composite film has obvious ellipsoidal grains with distinct grain boundaries and better crystallinity. Moreover, the performance of the film after annealing in different atmospheres of the slow annealing route was improved compared with that of the rapid annealing route after annealing in different atmospheres. Simultaneously, by changing the annealing atmosphere of the composite film, the film exhibited better magnetic optical properties and coupling properties after annealing in oxygen. In addition, this study showed that the dielectric constant and residual polarization value of the film increase under the action of magnetic field and illumination, and the maximum photomagnetic dielectric response (3.19%) and photomagnetic response (1.58%) are observed in the annealed film under the oxygen atmosphere of the slow annealing regime, indicating that the magnetoelectric coupling effect of the film is improved under the action of applied light.

中文翻译：

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快/慢速退火路线对BiFeO3/CoFe2O4多层薄膜磁性能和光电性能的影响

随着电子信息技术的发展，器件的小型化、轻量化和集成化对材料提出了更高的要求，二维复合多铁材料成为近年来的主要研究热点。然而，传统的固体多铁材料很难在外加电场/磁场的作用下直接切换磁/极化方向，限制了磁电耦合系数的提高。本研究通过改变退火路线和退火气氛制备了一系列BiFeO(BFO)/CoFeO(CFO)复合薄膜多铁材料，其显微结构、铁电性能、介电性能、光伏性能、磁性能和磁电耦合性能对复合薄膜的制备进行了系统研究。结果表明，在慢速退火路线下，复合薄膜具有明显的椭球晶粒，晶界清晰，结晶度较好。而且，慢速退火路线不同气氛退火后的薄膜性能较快速退火路线不同气氛退火后的性能有所提高。同时，通过改变复合薄膜的退火气氛，使薄膜在氧气中退火后表现出更好的磁光学性能和耦合性能。此外，本研究表明，在磁场和光照的作用下，薄膜的介电常数和残余极化值增加，并且在退火薄膜中观察到最大光磁介电响应（3.19%）和光磁响应（1.58%）在慢速退火方案的氧气气氛下，表明在施加光的作用下薄膜的磁电耦合效应得到改善。