Interfacial reconstruction, exchange bias and photocurrent effect in epitaxial Fe3O4/Co3O4 spinel heterostructure

• Published in: Applied surface science 2019-11, Vol.493, p.1236-1242
• Main Authors: Wang, Ping, Jin, Chao, Pang, Xin, Zheng, Wanchao, Gao, Guoqin, Wang, Dongshuo, Zheng, Dongxing, Dai, Haitao, Bai, Haili
• Format: Article
• Language: English
• Subjects: Epitaxial Fe3O4/Co3O4 heterostructure; Exchange bias; Interfacial reconstruction; Photocurrent
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.07.107

Fully spinel epitaxial Fe3O4/Co3O4 heterostructures were fabricated on the MgAl2O4 substrates by reactive magnetron sputtering, and the interfacial structure, magnetic and optical-electric properties were investigated. An interfacial CoxFe3-xO4 layer with a thickness of ~7 nm is formed between the Fe3O4 and Co3O4 layers through the interdiffusion. The interfacial CoxFe3-xO4 enhances the coercivity of the Fe3O4/Co3O4 heterostructures. The interfacial coupling between the ferromagnetic CoxFe3-xO4 and the antiferromagnetic Co3O4 also induces large exchange bias due to pinning effect. In addition, based on the strong optical absorption of the Co3O4 layer, the enhanced current (~79%) is achieved in the Fe3O4/Co3O4 heterostructures under irradiation of the 405-nm laser. Our work helps to understand the interfacial diffusion of the heterostructures, and reveals that the Fe3O4/Co3O4 heterostructures can be used in optical, electrical and magnetic multifunctional devices. [Display omitted] •Epitaxial Fe3O4/Co3O4 heterostructures were prepared by reactive magnetron sputtering.•An interfacial CoxFe3-xO4 layer is formed through the interdiffusion.•Interfacial coupling between the CoxFe3-xO4 and Co3O4 induces large exchange bias.•The enhanced current of ~79% is achieved under irradiation of 405-nm laser.