Magnetic excitations in the Ising-like layer compound (Co( γ-CH3-C5H4NO)6)(ClO4)2

The results of ESR experiments on the 2D antiferromagnetic Ising system (Co( gamma -CH3-C5H4NO)6)(ClO4)2 in the temperature range 1.2-4.2 K are reported. The observed absorption signals are found to originate from single-spin reversals and can be associated with nearest-neighbour configurations of different forms. The magnetic field dependence of the excitation energies has been interpreted on the basis of a rectangular (2D) Ising lattice with nearest-neighbour exchange interactions. The signal intensities show a behaviour that can qualitatively be explained in terms of the predictions for a 2D Ising model.