Structural, magnetic and optical properties of Ho-Co codoped BiFeO_3 nanoparticles

摘要

Structural, magnetic and optical properties of Bi_(0.85)Ho_(0.15)Fe_(1-x)Co_xO_3 (x=0.0-0.15) nanoparticles have been studied. X-ray diffraction patterns and Raman spectra demonstrate orthorhombic structure for all samples. Spontaneous magnetization of Ho-Co co-substituted BiFeO_3 nanoparticles increased up to 3.71 emu/g for x=0.15. Electron spin resonance analysis showed that the addition of Co~(2+) ions is likely to increase the spin canting angle and reduces anisotropy which favors the enhanced ferromagnetism. Optical studies in the spectral range from 1.1 to 5 eV showed two d-d crystal field transitions and three charge-transfer transitions with band gap variation from 2.60 to 238 eV.