The characteristics of the investigated materials, such as remanent magnetization (Mr), saturation magnetization (Ms), remanent polarization (2Pr) and saturation polarization (2Ps) continuously increase in the range of x from to . Origin of ferromagnetic and ferroelectric properties of materials will be discussed in this paper. | Vietnam Journal of Science and Technology 56 (1A) (2018) 219-235 ENHANCED FERROELECTRICITY AND FERROMAGNETISM OF (Y, Ni) CO-DOPED BiFeO3 MATERIALS Dao Viet Thang1, 2, *, Le Thi Mai Oanh3, Nguyen Manh Hung1, Do Danh Bich3, Nguyen Cao Khang2, Du Thi Xuan Thao1, Nguyen Van Minh3 1 Department of Physics, Hanoi University of Mining and Geology, 18 Pho Vien Street, Duc Thang Ward, North Tu Liem District, Ha Noi, Viet Nam 2 Center for Nano Science and Technology, Hanoi National University of Education, 136 Xuan Thuy Road, Cau Giay District, Ha Noi, Viet Nam 3 Department of Physics, Hanoi National University of Education, 136 Xuan Thuy Road, Cau Giay District, Ha Noi, Viet Nam * Email: daovietthang@ Received: 15 August 2017; Accepted for publication: 20 April 2018 ABSTRACT Multiferroic (x = , , , and ) called as (Y, Ni) co-doped BiFeO3 materials were synthesized by a sol-gel method and characterized by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) and vibrating sample magnetization (VSM) measurements. The result showed that all investigated materials present a single phase of the perovskite-type rhombohedral structure. Ferromagnetism and ferroelectricity of the materials have been affected by the (Y, Ni) co-doping, as a result the ferroelectric polarization and magnetization of the initial BiFeO3 material were enhanced with increasing concentration of Y3+ ion. It is attributed to the difference of the magnetic moments of Ni2+ and Fe3+ ions, as well as the Y3+-Fe3+ and Y3+-Ni2+ super-exchange interactions. The characteristics of the investigated materials, such as remanent magnetization (Mr), saturation magnetization (Ms), remanent polarization (2Pr) and saturation polarization (2Ps) continuously increase in the range of x from to . Origin of ferromagnetic and ferroelectric properties of Bi materials will be discussed in this paper. Keywords: multiferroic, ferromagnetism, .
