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Title: A Brillouin scattering study of La0.77Ca0.23MnO3 across the metal-insulator transition
Authors: Seikh, Md Motin
Narayana, Chandrabhas
Sudheendra, L
Sood, A K
Rao, C N R
Keywords: Colossal-Magnetoresistance Manganites
Perovskite Manganites
Acoustic Modes
Issue Date: 23-Jun-2004
Publisher: IOP Publishing Ltd
Citation: Journal Of Physics: Condensed Matter 16(24), 4381-4390 (2004)
Abstract: Temperature-dependent Brillouin scattering studies have been carried out on La0.77Ca0.23MnO3 across the paramagnetic insulator-ferromagnetic metal (I-M) transition (T-C similar to 230 K). The spectra show modes corresponding to a surface Rayleigh wave (SRW) and a high velocity pseudo-surface wave (HVPSAW) along with bulk acoustic waves (B1 and B2). The Brillouin shifts associated with the SRW and HVPSAW increase, whereas the B1 and B2 frequencies decrease, below T-C. The temperature dependence of the SRW and HVPSAW modes is related to the increase in the elastic constant C-11 across the I-M transition. The decrease in frequency across the I-M transition of the bulk modes is understood to be due to enhanced self-energy corrections as a result of increased magnon-phonon interaction across the I-M transition. Correspondingly, these modes show a large increase in the full width at half maximum (FWHM) as the temperature decreases. We also observe a central peak whose width is maximum at T-C.
Description: Restricted Access
Other Identifiers: 0953-8984
Appears in Collections:Research Papers (Prof. C.N.R. Rao)

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