Infrared spectral and elastic moduli study of NiFe2-xCrxO4 nanocrystalline ferrites

Nanocrystalline ferrites with general formula NiFe2-xCrxO4 (x=0.0-1.0) were prepared by the wet chemical method. Infrared spectra were scanned in the range of 300-800 cm(-1). Three absorption bands were observed in the infrared spectra, the high frequency band nu(1) is assigned to tetrahedral complex, low frequency band nu(2) to octahedral complex and a small band nu(3) is due to Fe3+O2- complex. The force constant, bond length, and the Debye temperature was determined by infrared spectra analysis. The force constant and bond length decrease with the increase in Cr3+ content x which suggests the weakening of the inter atomic bonding. The force constant, lattice constant, and pore fraction have been used to calculate elastic moduli such as stiffness constant, Young's modulus, bulk modulus, rigidity modulus, Poisson's ratio, wave velocity and the Debye temperature. The values of elastic moduli and the Debye temperature decrease with the increase in Cr3+ content x whereas Poisson's ratio almost remains constant. Results have been explained on the basis of inter atomic bonding. (C) 2012 Elsevier B.V. All rights reserved.