ESR Spectra of Charge Carriers in the α'- and β- Phases of (BEDT-TTF)2IBr2 Single Crystals

Abstract

High-frequency dynamic magnetic properties of quasi-two-dimensional organic conductors (BEDT-TTF)2IBr2ofα'- andβ-phases have been studied by Electron Spin Resonance (ESR) spectroscopy. The heating of crystals in theα'-phase is accompanied by their phase transition to theβ-phase, so, the Dyson distortion of the ESR line is appeared. Contributions from the crystal field and symmetry of the system as well as the orbital magnetic moment admixture to the total magnetic moment of charge carriers have been judged by the comparison of the orientation and temperature dependencies of the ESR spectra for theα'- andβ-phases. Experimental data have proved localized states of charge carriers either inα'- orβ-phases.