Anelastic spectroscopy study of the charge order transition of LiMn2O4

We studied the charge order transition of LiMn2O4 by means of anelastic spectroscopy, measuring the Young's modulus, E, and the elastic energy loss function, Q(-1). Our measurements confirm the occurrence of a phase transition at 296 K on cooling, showing a large hysteresis on heating. Around the transition temperature the Young's modulus shape reveals that there is at least one elastic constant, possibly c(44), decreasing lowering the temperature. Moreover the anelastic spectroscopy results confirm that the transformation is characterised by the coexistence of two phases in a narrow temperature range. The time constant of the transformation of the cubic into the orthorhombic phase sharply decreases lowering T from 296 to 290 K and then increases on further cooling to 289 K. The strong decrease of the time constant around 290 K can be related to the reduction of the c(44) elastic constant.