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Anomalous High Pressure Dependence of the Jahn-Teller Phonon in La0.75Ca0.25MnO3

Congeduti, A and Postorino, P and Caramagno, E and Nardone, M and Kumar, A and Sarma, DD (2001) Anomalous High Pressure Dependence of the Jahn-Teller Phonon in La0.75Ca0.25MnO3. In: Physical Review Letters, 86 (7). pp. 1251-4.


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Raman spectra of La0.75Ca0.25MnO3 have been collected for the first time over a wide pressure range 0 14 GPa using a diamond anvil cell. The frequency range explored 200 1100 cm21 and the very good quality of the data allowed us to carefully analyze the pressure evolution of the phonon modes of the MnO6 octahedra. The results show an abrupt transition at ~7.5 GPa with an evident deviation from the linear trend of the frequency of the Jahn-Teller phonon versus the applied pressure, accompanied by a strong phonon broadening. This behavior disagrees with the predicted insulator to metal transition and, on the contrary, indicates the occurrence of a new unpredicted phase in the very high pressure regime.

Item Type: Journal Article
Publication: Physical Review Letters
Publisher: American Physical Society (APS)
Additional Information: Copyright for this article belongs to American Physical Society (APS)
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 09 Jun 2004
Last Modified: 19 Sep 2010 04:12
URI: http://eprints.iisc.ac.in/id/eprint/73

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