Thermal properties of spinel Nickel-Zinc ferrite in the temperature range 400 to 1000 k

Abstract

Specific heat capacity (cp), thermal conductivity (λ), and thermal diffusivity (a) coefficients are measured for spinel ferrite system prepared according to the following composition: Ni1.67−xZnxFeSb0.33O4 where x = 0.00, 0.33, and 0.67. The specific heat capacity measurements indicate the presence of a magnetic phase transition from ferrimagnetic to paramagnetic. The Curie temperature decreases as the concentration of Zn ions increases. Below and above the magnetic transition region cp obey's Debye theory of specific heat. For the thermal conductivity coefficient, it is found that the main mechanism of heat transfer is due to phonons in the region below and above the magnetic phase transition, while in the magnetic transition the main mechanism is due to both, phonons and magnons. The role of electrons and phonons is negligible in the measured temperature range.