Pressure and temperature dependence of the Fano resonance in the Raman spectrum of $A_2FeMoO_6$ systems (A=Sr,Ca)

Marrocchelli, D and Postorino, P and Di Castro, D and Arcangeletti, E and Dore, P and Guidi, Cestelli M (2007) Pressure and temperature dependence of the Fano resonance in the Raman spectrum of $A_2FeMoO_6$ systems (A=Sr,Ca). In: Physical Review B, 76 . 172405-1-172405-4.

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Abstract

We report on Raman measurements carried out on $Ca_2FeMoO_6$ and $Sr_2FeMoO_6$ double perovskites as functions of pressure (0–15 GPa) and of temperature (298–370 K). The Raman spectrum of both the samples is characterized by a phonon peak at $\sim 460 cm^{-1}$ whose large asymmetric profile is ascribed to a Fano resonance. The careful data analysis provides in particular the Fano asymmetry parameter q which results to be nearly independent from pressure and temperature, thus suggesting a remarkable stability of both chargecarrier density and charge-lattice coupling. Finally, our data allow us to ascribe the conductivity transition previously observed around 2 GPa in $Sr_2FeMoO_6$ not to an intrinsic property but to the pressure-induced opening of intergrain percolation paths.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Additional Information:	Copyright of this article belongs to American Physical Society.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	02 Jun 2008
Last Modified:	19 Sep 2010 04:45
URI:	http://eprints.iisc.ac.in/id/eprint/14135

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