A comparative study of different concentrations of (Co/Ni/Cu) effects on elastic properties of Li–Mn ferrite employing IR spectroscopy and ultrasonic measurement

Abstract

Three series of divalent ions (Co2+/Ni2+/Cu2+) substituted into lithium-manganese ferrites were synthesized using a typical ceramic technique. Two different methods were used to investigate their elastic properties. Infrared (IR) spectroscopy showed two essential bands referring to the tetrahedral ‘υA’ and the octahedral ‘υB’ sites. The force constant, elastic wave velocity and elastic moduli of all specimens have been calculated from the results of IR spectroscopy. Using the ultrasonic pulse transmission (UPT) technique, the longitudinal and shear wave velocities were measured. Using these values; bulk modulus (B), rigidity modulus (G), Young's modulus (E), and Poisson ratio (σ) were determined. In comparison, the elastic moduli resulting from IR spectroscopy results were larger than those obtained from UPT measurements. Because the present ferrite systems are porous, the elastic moduli of the compositions from UPT have been adjusted to zero porosity by two models. The values of the adjusted elastic moduli have been shown to have the same trend as those of the uncorrected elastic moduli. Elastic parameters have generally improved dramatically for Li–Mn–Co ferrite and Li–Mn–Ni ferrite compared to Li–Mn–Cu ferrite. Higher elastic moduli values have been obtained in Li–Mn–Co spinel ferrites, suggesting that such materials are ideal for use in core shapes. Two methods were used to evaluate the Debye temperature of all compositions.