ESR study of the orbitally induced Peierls phase transition in polycrystalline CuIr2S4CuIr2S4

In this work, we investigate the polycrystalline CuIr2S4CuIr2S4, which exhibits an orbitally induced Peierls phase transition at TMI≈230K, by the electron spin resonance (ESR) spectroscopy. A corresponding change occurs to the ESR spectra, as well as in the obtained ESR parameters such as resonance field Hr and g  -factor (geff)(geff). It is suggested that the ESR signals originate from the paramagnetic moments caused by lattice defects, which are affected by the spin-dimerization transition. However, ESR signals from a few non-dimerized Ir4+Ir4+ maybe also exist. In addition, an anomalous change below ∼50K is detected by the ESR parameters. A possible explanation was proposed to interpret the experimental results.