The peculiarities of the magnetic resonance in Cs Er (Mo O4)2

The magnetic resonance of Cs Er(Mo O4)2 is studied in a wide range of frequencies (11-190 GHz) and temperatures (1.8-35 K). It is shown that this compound belongs to the Ising magnetics characterized by high anisotropy of spin-spin interaction. The observed triplet structure of the spectrum is considered to be due to the Ising ferromagnetic chains along the b-axis.The interactions within a chain are estimated. The additional absorption line observed at H parallel b is explained in terms of the four-level model as a transition between the ground and excited doublet states. A spectral feature is found along the c-axis, which is related to the structural phase transition induced by the external magnetic field