Effect of Ho, Mn co-doping on the structural, optical and ferroelectric properties of BiFeO_3 nanoparticles

摘要

Multiferroic Bi_(1-x)Ho_xFe_(0.95)Mn_(0.05)O_3 (x = 0.025, 0.05, 0.075, 0.10 and 0.1) powder samples were successfully prepared by sol-gel technique. The effect of Ho, Mn co-doping on the properties of structural, electrical, optical and ferroelectric have been systematic investigated. X-ray diffraction (XRD) patterns reveal that Ho, Mn co-substitution leads to a structural transition. The scanning electron microscope (SEM) shows that the grains of all the samples are asymmetrical and anomalous in shape and the particle size of the samples decrease from 200 to 500 to ~100 nm with doping Ho and Mn in BFO. UV-Visible absorption spectra exhibit that co-doping can reduce the direct optical band gap from 2.40 to ~1.77 eV after doping Ho and Mn. Electric measurements demonstrate that both of the leakage current density and ferroelectric properties can be improved obviously by Ho and Mn co-doping as a result of the suppression of oxygen vacancies.