Thermal conductivity of the ferrites Ni0.65Zn0.35CuxFe2?xO4

A series of samples of the type Ni_0.65Zn_0.35Cu_xFe_2?xO₄ (x=0, 0.1, 0.2, 0.3, 0.4 and 0.5) were prepared by a ceramic technique. The existence of a single phase was confirmed by X-ray studies. The thermal conductivity and specific heat were measured at 53°C. The thermal conductivity had a minimum value atx=0.3, due to the maximum porosity at this composition. The phonon frequency was estimated to have an optimum value at x=0.3, due to the increase in phonon scattering.