Nanocrystalline MnZn ferrites for power applications

Mn-Zn ferrite core has been widely used in electronic applications such as transformers, choke coils, noise ¿lters, recording heads and high-frequency powder electronics, etc because of high intial permeability, high saturation magnetization, low eddy current and low coercivity. The most recent reason for upsurge in ferrite interest has been the development of the new, small, efficient power supplies using solid state switching known as switch mode power supplies (SMPS). These power supplies are being used in computers, laptops, microprocessor, telecommunication and entertainment applications. The transformer used in SMPS is generally constructed with bulk magnetic materials, such as MnZn ferrite or Co-type amorphous soft magnetic thin ribbon. But in practice it was found that these materials, output power increases and efficiency of transformer deteriorated with an increase of load current. These problems can be overcome if we select a magnetic material with high permeability at lower frequency and with low power loss at megahertz frequency. The high permeability and low power losses can be achieved using nanocrystalline MnZn ferrites in place of micro-magnetic MnZn ferrites.