Electron spin resonance studies on MnCl₂- and CuCl₂- graphite intercalation compounds

We present experimental data of the electron spin resonance in MnCl₂- and CuCl₂-graphite intercalation compounds (GIC) with various angles between the crystal axis and the external field. The MnCl₂-GIC is regarded as a quasi-two dimensional antiferromagnet with a triangular lattice, but the CuCl₂-GIC have an in-plane structure of a distorted triangular lattice. The result for the MnCl₂-GIC shows that the linewidth is explained roughly by the 2D structure model at high temperatures but it becomes anisotropic below about 30K. This behavior is not varied among the samples with stage-1 and 2. The result for CuCl₂-GIC shows that the angular dependence of the resonance field is anisotropic in the ab-plane. Also no frequency dependence of the g-value in X, K and Q bands was found.