Influence of the Cooling Rate at Thermal Sintering on the Structure and Magnetic Properties of Ferrite Ceramics

The influence of the cooling rate during sintering of lithium-titanium-zinc-manganese spinel ferrite on its structural, magnetic and electric characteristics was studied. The ferrite was sintered in air at 1283 K for 120 min. Cooling rates were 0.06 K/s and 7.8 K/s. It was established that the observed changes in the characteristics when using slow and quenching cooling are due to the different levels of the near-surface ferrite layers oxidation. For quench ferrite, the Curie temperature of 530 K, the activation energy of electrical conductivity of 0.35 eV in the bulk of the samples, and the magnetic anisotropy constant of 2.6·10 -3 J/m 3 (at 300 K) were obtained. Slowly cooled ferrite was characterized by higher values of Curie temperature (560 K), the magnetic anisotropy constant (2.9·10 -3 J/m 3 ), and the activation energy of electrical conductivity (0.80 eV).