Dogra, Sugandha and Singh, Jasveer and Sharma, Nita Dilawar and Samanta, K. and Poswal, H. K. and Sharma, S. M. and Bandyopadhyay, A. K. (2014) Phase progression via phonon modes in lanthanide dioxides under pressure. Vibrational Spectroscopy, 70. 193 -199. ISSN 0924-2031

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Abstract

The present paper reports the phase progression in nano-crystalline oxides PrO2 and CeO2 up to pressures of 49 GPa and 35 GPa, respectively, investigated via in situ Raman spectroscopy at room temperature. The samples were characterized at ambient conditions using X-ray diffraction (XRD), AFM, and Raman spectroscopy and were found to be cubic with fluorite structure. With an increase in applied pressure the cubic bands were seen to steadily shift to higher wavenumbers for both the samples. However, we observed the appearance of a number of new peaks around a pressure of about 34.7 GPa in CeO2 and 33 GPa in PrO2 which were characteristic of an orthorhombic alpha-PbCl2 type structure. The mode Gruneisen parameters for both the phases were obtained from the pressure dependence of frequency shifts. On decompression, the high pressure phase existed down to a total release of pressure.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/S Elsevier.
Uncontrolled Keywords:	High pressure Phase transitions Raman spectroscopy CeO2PrO2
Subjects:	Chemistry Spectroscopy
Divisions:	UNSPECIFIED
Depositing User:	Dr. Rajpal Walke
Date Deposited:	30 Oct 2015 06:56
Last Modified:	30 Oct 2015 06:56
URI:	http://npl.csircentral.net/id/eprint/1458

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