Structural and Ferromagnetic Properties of Ho-Doped BiFeO_3 Films

摘要

In order to improve the structural and ferromagnetic property of BiFeO_3, the effects of Ho~(3+) doping is systematically investigated. Pure BiFeO_3 and Ho-doped BiFeO_3 Thin films are fabricated by sol-gel method, and the phase structure, morphology, crystalline structure, ferromagnetic are characterized by XRD, SEM, Raman spectra and VSM, respectively. The XRD patterns of the samples indicate that all the compounds crystallize in rhombohedral distorted perovskite structure with space group R_3C and the Ho substitution can suppress the intrinsic formation of the miscellaneous phase. The SEM proves that along with the increasing of Ho concentration, the surface roughness of BiFeO_3 is decreased due to the reduction of defects in the preparation. From the Ramar spectroscopy, it is found that the peak intensity of 8 modes in Bi_(1-x)Ho_xFeO_3 are increased and the modes shift to higher wave number. Besides, the VSM results show that the ferromagnetic of the samples is enhanced with increasing of Ho concentration. When x=0.1, Ms is improved to be 4.8emu/g. The results can prove that the Ho~(3+) doping can reduce the volatilization of Bi~(3+) , decrease the concentration of oxygen vacancies and improve the room-temperature ferromagnetic of BiFeO_3