Electron Spin Resonance Study on Second-Stage MnCl₂-Graphite Intercalation Compound

抄録

The second-stage MnCl₂-graphite intercalation compound (GIC) is a two-dimensional (2D) antiferromagnet with uniaxial anisotropy on the triangular lattice. It undergoes two magnetic phase transitions at T_c1 and T_cu (T_c1=1.1 K and T_cu=46.7 K). The electron spin resonance of this compound have been measured at 9.43 GHz over the temperature range 4.2 K≤T≤300 K. The angular dependence or the line-width is or the (3 cos²θ−1)²-like form at 300 K (θ is the angle between the external field H and the c-axis), indicating the 2D character of this compound. The line-width at θ=90° (H⊥c) increases monotonously with decreasing temperature in the temperature range T_c1≤T≤T_cu, while the line-width at θ=0° (H⁄⁄c) shows a local minimum between T_c1 and T_cu.