Magnetic properties of MnZn ferrite with ultra-fine grain structure

Nanostructured ferrites have been prepared by milling starting from commercial ferrite powders. Subsequent compaction and sintering were applied to obtain cylindrical pieces. The magnetization as a function of the grain size follows the non-magnetic grain boundary model. The boundary thickness is estimated as about 1.5 nm, which is consistent with that calculated from the Mössbauer absorption areas. Due to the high lattice distortion, the small exchange length impedes the averaging of the anisotropy.