Structural link to precursor effects

Abstract

We investigate the origin of precursor effect associated to magnetic phase transitions in a quasi-one-dimensional system Ca₃Co₂O₆, employing extended X-ray absorption fine structure technique. Experimental results reveal unusual changes in the Co-O bond lengths in CoO₆ units nucleating at a temperature T^∗, where the precursor effect occurs. The corresponding Debye-Waller factors representing disorder effect exhibit anomalous evolution across T^∗. These results reveal a unique link between the local structural changes and the precursor effect that needs to be considered in the understanding of various phase transitions.