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This communication presents the effect of high energy ball milling induced strain and grain size reduction on Infrared spectral evolution, elastic, optical and thermodynamic properties of un-milled and 3, 6 and 9 h. milled samples of spinel ferrite composition, Ni 0.5 Zn 0.5 Fe 2 O 4 , studied by means of X-ray powder diffractometry and infrared spectroscopy measurements at 300 K. A simple approach is used for force constants determination and found to be quite satisfactory. The elastic moduli, elastic wave velocities, Debye temperature, threshold energy, molar heat capacity, refractive index, reflectivity, jump rate of charge carriers for the ferrites have been determined and they are found to vary in accordance with variation of lattice constant and milling induced strain as a function of milling time. No effect on the elastic parameters is observed due to milling induced grain size reduction. Elastic constants calculated using the relation, K o = (60 + 490 * S N ) and heterogeneous metal mixture rule are in agreement with those determined from IR and XRD patterns analysis, validates the applicability of these approaches. The lattice energy for polycrystalline ferrite materials and single crystalline counterpart as well as electronic contribution to molar heat capacity has been calculated. |
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