New MnZn Ferrite with Low Losses at 500kHz Over a Broad Temperature Range

AbstractIn this article the development of a medium frequency MnZn ferrite with low losses over a broad temperature range is described. This has been realized through optimization in the design of the unit cell lattice with the addition of the appropriate dopants. The addition of Tin (Sn) ions results to an increase of the specific resistivity. Consequently the power losses at medium frequencies, 500kHz, are decreased. Cobalt (Co) ions possess opposite sign anisotropy constant of the host lattice. Their introduction compensates the already existing lattice anisotropy. As a result, the temperature dependence of the anisotropy constant of the host lattice decreases and this leads to an increase of the permeability and decrease of the power losses. The newly developed MnZn ferrite exhibits initial permeability of 1656 at 10kHz, 0.1 mT, 25°C, power losses 783 mW cm-3 at 25°C and 656 mW cm-3 at 80°C, 500kHz, 100 mT and is therefore ideal for applications where low losses with small dependency on the working temperature are demanded