The B-site Moessbauer linewidth in Fe3O4

It is found that the linewidth of the B-site Moessbauer spectrum of an Fe3O4 single crystal at room temperature is strongly dependent on the direction of the externally applied magnetic field. The broadening of the line 1B observed in polycrystalline materials is concluded to be largely determined by magnetic dipolar and electric quadrupolar effects, and therefore cannot serve as proof for an electron hopping model. (Auth.)