Static magnetic order in the triangular lattice ofLixNiO2(x≤1): Muon-spin spectroscopy measurements

Abstract

In spite of numerous experimental and theoretical reports on LiNiO2, no consistent picture has emerged of the nature of its ground state. We have investigated the LixNiO2 system 0.1x 1 by means of muon-spin spectroscopy and susceptibility to gain further insight from the effects of varying the magnetic ion concentration. Static magnetic order, most likely to be incommensurate to the spatial lattice period, was found for x 0.6 at low temperatures T, while disordered magnetism due to localized Ni moments appears for x =1 / 2–1 / 4 and, finally, Li0.1NiO2 exhibits almost fully nonmagnetic behavior down to the lowest T measured. The ground state of LiNiO2 is inferred to be a “static but short-range” A-type antiferromagnetic ordered system, in which the Ni 3+ moments align ferromagnetically along the c axis in the NiO2 plane with an incommensurate modulation probably due to canting of the Ni 3+ moments, but align antiferromagnetically between adjacent NiO2 planes.