Exploring Origin of Ferromagnetism from Abnormal Exchange Bias in Mn-Doped BiFeO3 Nanoparticles

摘要

Monocrystalline BiFe1-xMnxO3 (x = 0, 0.10, 0.15, 0.20) were synthesized by co-precipitation method. Saturation magnetization M-s increased from 0.05 emu/g at x = 0 to 0.5 emu/g at x = 0.20, which indicated the enhancement of ferromagnetism with the increase of x. Abnormal exchange bias field changing with different x in same field cooling process was observed, in which maximum value 2000 Oe was obtained at x = 0.10. Since Mn ions occupied the position of Fe ions, the increase of net magnetic moments and the decrease of antiferromagnetic exchange integrals J(AFM) were obtained, which eventually led to maximum exchange bias field at x = 0.10.