Lithium-cobalt mixed ferrites of different compositions have been prepared by the double-sintering technique, the final sintering temperature being 1100 deg C. Elastic properties of these mixed ferrites have been investigated as a function of composition. From the experimentally observed values of longitudinal (V_1) and shear (V_s) wave velocities, Young's (E) and Rigidity (n) moduli are calculated. As the ferrites under investigation are porous, the elastic moduli have been corrected to zero porosity using Hasselman and Fulrath's formulae. It is observed, from the corrected values of elastic moduli, that the moduli are increasing with increasing Cobalt content. The Poisson's ratio for all the samples was centered around a value of 0.2. Following Wooster's work, the variation of the elastic moduli with composition was interpreted in terms of the binding forces between the atoms. Debye temperatures (theta_D) of these mixed ferrites have been calculated using Anderson's formula. It is observed that the value of theta_D increases with Cobalt doping. The average sound velocity (V_m) is found to increase linearly with Debye temperature.
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