Electron spin resonance probed suppressing of the cycloidal spin structure in doped bismuth ferrites

The weak magnetism of bismuth ferrites Bi1−xDyxFeO3 with x=0.0 to 0.40 is studied via the electron spin resonance (ESR) of X-band (9.53 GHz) at various temperatures. The g-factor of pure BiFeO3 is 2.0, which originates from its cycloidal spin structure; while for the doped Bi1−xDyxFeO3 samples with x>0.10, ESR spectra reveal a second phase with a different g-factor around 1, which is attributed to the homogeneous magnetized phase of Bi1−xDyxFeO3. The temperature dependent ESR data further suggest a picture of the doping-induced transformation from cycloidal to canted antiferromagnetic state.