Comparison of Local Crystal Structure and Magnetic Properties of Cation substituted LiNiO2 Compositions

Publication date: Available online 13 April 2019Source: Materials Research BulletinAuthor(s): M K Majee, A K Nigam, P A BhobeAbstractWe investigate the change in local crystal structure and its impact on the magnetic ground states of LiNi0.5X0.5O2 (X = Mn, Co) and LiNi0.75Y0.25O2 (Y = Fe, Al) and contrast it against LiNiO2. The solid-state synthesis route adopted here introduces some anti-site disorder in the final compositions due to the volatile nature of Li ions. Powder X-ray diffraction (XRD) profiles were hence recorded using a rotating anode X-ray source to determine the percentage of anti-site disorder, and phase purity of all the compositions. Rietveld refinement of the XRD profiles confirms the symmetry and provides the estimation of unit cell parameters. Near-edge X-ray absorption spectra verified the oxidation state of various cations present in the compositions. Analysis of the extended X-ray absorption fine structure spectra identify the signatures of Jahn-Teller distortion in Ni3+ rich compositions. Changes in NiO6 octahedral environment has a much deeper impact on the magnetism of these compositions.Graphical abstract
Source: Materials Research Bulletin - Category: Materials Science Source Type: research