ESR study of new layered semiconductor Ga2Cr1.33Se5

The Ga2Cr1.33Se5 compound is a layered semiconductor and it can be visualised as layers of chromium ions with nearest-neighbour distances of 0.378 nm within layers and interlayer distances are alternately of 0.626 and 0.923 nm. The ESR measurements of a single crystal as a function of temperature were performed; a single Lorentzian-type spectrum was observed for T>20 K. The observed angular anisotropy of the linewidth has been satisfactorily explained on the basis of the anisotropic exchange model. The peculiarities of ESR parameters (intensity, ΔB, Br) below T≅20K can be interpreted taking into account two mechanisms: (i) presence ferromagnetic, exchange interactions between in-plane chromium ions and antiferromagnetic interplane coupling which means magnetic dimensionality crossover from 2- to 3-d system; (ii) appearance of a spin disorder.