Effect of calcination temperature on the physical properties of LiFe5O8 nanostructures

The structural properties of LiFe5O8 nanostructures, which were synthesized using a thermal treatment method, were investigated using different characterization methods. The XRD, FESEM and TEM results showed a phase transition from uncompleted alpha-LiFe5O8 and beta-LiFe5O8 phases to completed alpha-LiFe5O8 phase when the growth calcination temperature shifted from 873 to 973 K. The crystallization was completed at 973 K, revealed by the absence of organic absorption bands in the FT-IR spectra. The results of band gap energy which were studied by UV-vis spectroscopy indicated that when calcination temperature increased, the appraised band gap energy of LiFe5O8 nanostructures decreased. Laser Raman analysis was used to determine the peaks of the synthesized LiFe5O8 nanostructures accurately and to differentiate between the alpha-LiFe5O8 and beta-LiFe5O8 phases around 217 cm(-1). The results of a vibrating sample magnetometer (VSM) indicated that the magnetic properties differed between these nanostructures so that saturation magnetization and coercivity increased when the calcination temperature increased. The obtained results from electron paramagnetic resonance (EPR) spectroscopy demonstrated that as the growth calcination temperature shifted from 673 to 873 K, the results of g value and Delta H-pp increased up to the maximum value and then reduced for calcined sample at 973 K. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.