MICROSTRUCTURE OF MANGANESE ZINC FERRITES

The high quality manganese zinc ferrites, mainly for higher permeabili ties or higher operating frequencies, require a precise control of the microstructure of sintered ferrites, especially the grain size and gr ain size distribution, the chemical composition and structure of the g rain interfaces or grain boundaries. The high resolution scanning tran smission electron microscopy is a useful method to get reliable inform ation between microstructure and magnetic properties of the ferrites. The experimental investigations showing the existence of planar defect s, crystalline and amorphous interfaces between the grains. Lorentz im ages showing magnetic boundaries, which clearly cross the grain bounda ries. Further improvements of the soft magnetic Mn-Zn-ferrites are pos sible in connection with a better homogeneity of the chemical composit ion and an optimised microstructure.