Conductivity improvement of Li-Co-Yb ferrite

The effect of gamma -irradiation on some physical properties of rare earth ferrite of the general formula Li0.5+zCozYbxFe2.5-2z-xO4, (z = 0.1, x = 0.0 0, 0.025, 0.050,..., 0.200) was discussed. The temperature dependence of th e polarization and resistance was studied in the range (300 K less than or equal to T less than or equal to 700 K) at different frequencies (10 kHz le ss than or equal to f less than or equal to 1 MHz). The relaxation time and the activation energy were calculated for gamma doses of 1 and 3 Mrad. Als o, a comparison was made between the ac resistance, before and after irradi ation, for the samples with different Yb concentrations (0.0 less than or e qual to x less than or equal to 0.2). The results after irradiation with a I Mrad dose of gamma -rays showed that the resistance at the critical conce ntration decreases from 800 to 25 k Omega, at room temperature. Furthermore , with increasing temperature the resistance ranged from R approximate to 1 30 k Omega at T approximate to 310 K to R approximate to 0.13 k Omega at T approximate to 640 K. Thus, it is possible to improve the conductivity of t his type of rare earth ferrite material to be used in technological applica tions at room temperature as well as at high temperatures.