Temperature Effect on Vibrational Properties of La0.7Sr0.3MnO3
Temperature Effect on Vibrational Properties of La0.7Sr0.3MnO3
Talati, M.; Jha, P. J.
Temperature dependence of phonons spectra and allied properties of rhombohedral La0.7Sr0.3MnO3 are investigated by using the lattice dynamical method. A tendency of phonon mode to instability causing JT lattice distortion is reflected in a softening of the stretching mode in the phonon dispersion curve of La0.7Sr0.3MnO3 at both 1.6 and 300 K. While the A(1g) mode softens because of gradual decrease in MnO6 rotations, the stretching mode hardens upon reduction in temperature. The distinct features of phonon modes at different temperatures are also reflected in the calculated phonon density of states. Other thermal properties such as specific heat, the Debye temperature, and Gruuneisen parameter are also presented. The decrease in the Debye temperature at 300 K indicates the effect of temperature in lattice softening. Anomalously high value of the Gruneisen parameter points out the presence of anharmonic lattice modes.
Keywords: Phonon dispersion; phonon density of states; colossal magnetoresistance; manganites
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International Journal of Modern Physics B 23(2009)23, 4767-4777
DOI: 10.1142/S0217979209053783
Cited 1 times in Scopus
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Permalink: https://www.hzdr.de/publications/Publ-13588
Publ.-Id: 13588