Doping effects on the phase transition of LiMn2O4by anelastic spectroscopy and differential scanning calorimetry

A comparative study of Li1-xMn2-xO4 (0 <= x <= 0.08) by means of anelastic spectroscopy and differential scanning calorimetry (DSC) is reported. DSC measurements, in agreement with previous literature, can detect a phase transition accompanied by latent heat only for x < 0.04. This fact has been generally accepted as a proof that the transformation is suppressed by doping. In this paper we show that DSC alone is not sufficient to provide a correct answer to the problem. Indeed, anelastic spectroscopy, which is a technique extremely sensitive to rearrangements of atoms in the lattice, indicates that the transition survives up to x = 0.08, is shifted towards lower temperatures, and becomes of an order higher than the first, so that there is no associated latent heat. (c) 2006 Elsevier B.V. All rights reserved.