Electron energy-loss spectroscopy of LiMn_2O_4, LiMn_(1,6)Ti_(0,4)O_4 and LiMn_(1,5)Ni_(0.5)O_4

摘要

The dielectric properties of LiMn_20_4, LiMn_(1.6)Ti_(0.4)0_4 and LiMn_(1.5)Ni_(0.5)0_4 powders, synthesized by sol-gel method, were determined by analyzing the low-loss region of the electron energy-loss spectroscopy (EELS) spectrum in a transmission electron microscope. From these data, the optical joint density of states (OJDS) was obtained by Kramers-Kronig analysis. Since maxima observed in the OJDS spectra are assigned to interband transitions above the Fermi level, these spectra can be interpreted on the basis of calculated density of states (DOS), carried out with the CASTEP code. Experimental and theoretical results are in good agreement.