Structural and magnetic properties of LiNi0.75Al0.25O2

Abstract

The polycrystalline sample of LiNi0.75Al0.25O2 was prepared by standard solid state route and characterized for its magnetic properties. The associated local crystal structure was studied by recording the Ni K-edge XAFS. Room temperature powder X-ray diffraction patterns reflect the sample to be in single phase and crystallize in the hexagonal setting with space group R-3m. Temperature dependent magnetization performed over a temperature range 2 to 300 K indicates a complex magnetic behavior. Room temperature XAFS studies reveal lifting of the degeneracy of the octahedrally coordinated Ni yielding two different Ni - O bond lengths. The scenario with Jahn-Teller distortion of the trivalent nickel ion in the low spin state t2g6eg1 helps to understand the magnetic properties of this compound. Possibility of small percentage of Ni ions diffusing to Li site is also discussed. © 2018 Author(s).