Temperature dependence of magnetic behaviour in very fine grained, spark plasma sintered NiCuZn ferrites

Abstract

Recently, using spark plasma sintering technique, a family of very fine grained, fully dense NiCuZn ferrites have been produced which show constant permeability up to several 10 MHz. These Ferrites can be used for filtering purposes in high frequency applications where a wide frequency band is required. In this paper we study the magnetization processes taking place in these nano grained materials, in the frequency interval of 100kHz to 5MHz. Using a fluxmetric hysteresis graph, permeability, loss and BH loops are measured at different temperatures, from -5• C to 110• C. Results are compared to the behaviour of micrometric grain size Ferrites, which are commonly used for power electronic and high frequency applications.

Soft Magnetic Materials and Applications

“…Experience shows that Rayleigh law is well obeyed in ferrites up to 25 mT and over 100 kHz in highly resistive NiZn type ferrites (see e.g. [1])…”

“…Usually in low frequency applications such as AC machines and transformers, as well as in standard characterization conditions, the induction is sinusoidal. The average of a squared sinus being 1 2 , we end up with the well known formula, where B p denotes the peak value of the induction:…”