Magnetic frustration and spin glass behaviour in layered lithium oxide, LiNi$_{0.65}$Co$_{0.25}$Mn$_{0.10}$O$_{2}$.

Samples of Li$_{x}$Ni$_{0.65}$Co$_{0.25}$Mn$_{0.10}$O$_{2}$ with different amount of Li (x) have been investigated with ac and dc SQUID magnetometry, X-ray diffraction as well as with neutron scattering. The Li$_{x}$Ni$_{0.65}$Co$_{0.25}$Mn$_{0.10}$O$_{2}$ exhibit a rhombohedral structure (space-group $R\bar {3}m)$ with non-magnetic Li$^{+}$ layers alternating with transition metal (TM) slabs with edge-sharing oxygen octahedras. The nickel slabs contain several intralayer interactions of both antiferromagnetic (AFM), ferromagnetic (FM) type, e.g. 90$^{o}$ Ni$^{2+}$-O-Mn$^{4+}$ and 90$^{o}$ Ni$^{3+}$-O-Ni$^{3+}$, respectively. Also, the presence of Ni$^{2+}$ in the Li-plane further induces AFM and FM couplings due to 180$^{o}$ superexchange interactions between Ni$^{2+}$ in the Li-plane and TM- ions present in the slabs. The resulting magnetic structure shows no evidence of long range order due to a high degree of spin frustration, thus yielding magnetic properties reminiscent of a spin glass.