High-permeability MnZn ferrites with flat µ-T curves

For various applications ferrite materials are required with a high permeability and a small variation of the permeability in a temperature range from 0 to 60°C. From a discussion of the theoretical conditions necessary for the occurrence of a high permeability and a flat μ-T curve in MnZn ferrites, it is clear that these two requirements are controversial. However, by a proper choice of the composition and a correct application of the method of reoxidation during sintering, a good compromise can be obtained. In the laboratory a permeability variation Δμ of less than 5 percent has been realized for a permeability level of 7500 in the above temperature range.