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Title: Phase transitions in delafossite CuLaO{sub 2} at high pressures

Structural stability of a transparent conducting oxide CuLaO{sub 2} at high pressures is investigated using in-situ Raman spectroscopy, electrical resistance, and x-ray diffraction techniques. The present Raman investigations indicate a sequence of structural phase transitions at 1.8 GPa and 7 GPa. The compound remains in the first high pressure phase when pressure is released. Electrical resistance measurements carried out at high pressures confirm the second phase transition. These observations are further supported by powder x-ray diffraction at high pressures which also showed that a-axis is more compressible than c-axis in this compound. Fitting the pressure dependence of unit cell volume to 3{sup rd} order Birch-Murnaghan equation of state, zero pressure bulk modulus of CuLaO{sub 2} is determined to be 154(25) GPa. The vibrational properties in the ambient delafossite phase of CuLaO{sub 2} are investigated using ab-initio calculations of phonon frequencies to complement the Raman spectroscopic measurements. Temperature dependence of the Raman modes of CuLaO{sub 2} is investigated to estimate the anharmonicity of Raman modes.
Authors:
; ; ;  [1] ;  [2] ; ;  [3]
  1. Solid State Physics Division, Bhabha Atomic Research Center, Mumbai 400 085 (India)
  2. High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Center, Mumbai 400 085 (India)
  3. Chemistry Division, Bhabha Atomic Research Center, Mumbai 400 085 (India)
Publication Date:
OSTI Identifier:
22273673
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 13; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COPPER COMPOUNDS; ELECTRIC CONDUCTIVITY; EQUATIONS OF STATE; LANTHANUM OXIDES; PHASE STABILITY; PHASE TRANSFORMATIONS; PHONONS; POWDERS; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; RAMAN SPECTROSCOPY; TEMPERATURE DEPENDENCE; X-RAY DIFFRACTION