CORRELATION BETWEEN LOSSES, COMPLEX PERMEABILITY AND ELECTRON-DIFFUSION IN POWER FERRITES

The contribution of electron diffusion to power losses was studied. Fr om the frequency dependence of complex permeability, the damping and r esonance parameters were determined in the frame of the forced oscilla tor model. The damping constant correlates well with the difference be tween total and hysteresis losses. The complex permeability, the loss factor and the conductivity were measured as a function of frequency b etween 80 K and 300 K. From the tan delta - maximum over temperature f or different frequencies an activation energy was calculated. Its valu e agrees with the activation energy for the conductivity, showing a cl ear correlation between tan delta and electron diffusion for power mat erials. In an attempt to influence the electron diffusion-driver, magn etic behavior, electric fields perpendicular to the magnetic flux were applied to ring cores. The dependence of magnetic properties on elect ric fields as a function of temperature, frequency, amplitude and phas e shift between magnetic and electric fields was measured. A dramatic effect on power losses in dependence of field direction was observed, showing a maximum at the temperature of the secondary permeability max imum.