Measuring and modeling broadband magnetic losses versus temperature and aging effects in CoO-doped Mn-Zn ferrites

We analyze the physical mechanisms associated with addition of CoO to sintered Mn-Zn ferrites and the ensuing stabilization versus temperature of their magnetic properties. We determine, in particular, the value and behavior of the magnetic anisotropy as a function of doping and temperature and we model in physical terms the evolution of the energy loss in the investigated frequency (DC - 1 GHz) and temperature (20 °C - +130 °C) ranges. We show that magnetic aging by long exposure of the CoO-doped ferrites at 200 °C is minimized by additional TiO
₂
doping. This is observed to restrain the increase of the extra-anisotropy induced by directional ordering of the Co
²⁺
cations.