Development of low loss Mn-Zn ferrites having the fine microstructure

We studied relations between the microstructure and core loss of Mn-Zn ferrites for power supplies. As the results, we found that the lowest core loss was achieved at 100 kHz and 200 mT condition when the average grain size were 15 to 17 /spl mu/m. Then, we examined the effect of the third element in addition to CaO-SiO/sub 2/ on their deposition behavior in the grain boundary and we found the some additives such as Nb/sub 2/O/sub 5/, Ta/sub 2/O/sub 5/ and ZrO/sub 2/ which reduce the core loss. Further more, by optimizing the sintering condition, we were able to obtain the extremely low loss Mn-Zn ferrite material for power applications.