Raman study of anharmonic effects inPr0.5Ca0.5MnO3thin films

Autor:	Dimitrios Lampakis, A. Tatsi, E. Liarokapis, Wilfrid Prellier, E. L. Papadopoulou, B. Mercey
Rok vydání:	2003
Předmět:	symbols.namesake Phase transition Materials science Colossal magnetoresistance Condensed matter physics Normal mode Anharmonicity Hydrostatic pressure Relaxation (NMR) symbols Thin film Raman spectroscopy
Zdroj:	Physical Review B. 68
ISSN:	1095-3795 0163-1829
DOI:	10.1103/physrevb.68.024432
Popis:	We report low-temperature and hydrostatic pressure Raman measurements in Pr 0 . 5 Ca 0 . 5 MnO 3 thin films grown on SrTiO 3 and LaAlO 3 substrates. From the low-temperature dependence of the modes related with the Jahn-Teller distortions of the octahedra, it is found that an increase appears in their relative intensities at temperatures close to the charge-ordering phase transition. Two rotational modes of vibration of the octahedra show an anharmonic behavior. Strains from the substrate do not induce any shift or new modes in the Raman spectra probably due to their relaxation from the interface towards the surface of the films. From the different orientation of the two films, the symmetry of certain modes has been identified.
Databáze:	OpenAIRE
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