Influence of magnetic properties on electrochemical activity of LiNi0.5Fe0.5O2

LiNi0.5Fe0.5O2 is prepared by a sol–gel method and the sample is heat-treated to various temperatures to characterize its physico-chemical properties. Calcination of the precursor at 673 K produces powders of tetragonal and hexagonal phases. Subsequent heat treatment at 873, 1073 and 1273 K results in a pure hexagonal phase. Vibrating sample magnetometer (VSM) studies show that the tetragonal phase is magnetically stronger than the hexogonal phase. Room-temperature Mössbauer studies reveal magnetic ordering for the tetragonal phase and the paramagnetic nature of the hexagonal phase. The hexagonal phase is magnetically ordered at 77 K. By comparing the value of the hyperfine field with the bulk magnetization value at 77 K obtained from VSM, it is concluded that the magnetic ordering cannot be ferromagnetic but should be antiferromagnetic.