Pressure and temperature dependence of the lattice dynamics of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi><mml:mi mathvariant="normal">Al</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>investigated by Raman scattering experiments and<i>ab initio</i>calculations

Pellicer‐Porres, J.; Martínez‐García, D.; Segura, A.; Rodríguez‐Hernández, P.; Múñoz, A.; Chervin, J. C.; Garro, N.; Kim, D.

doi:10.1103/physrevb.74.184301

Cited by 96 publications

(67 citation statements)

References 32 publications

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“…However, both compounds show additional features (Figs. 2 and 3) similar to those observed in other delafossite compounds such as CuAlO 2 [34] and CuGaO 2 [25]. In agreement with ab initio calculations, these additional modes in CuAlO 2 are attributed to non-zero wavevector phonons which are normally forbidden by Raman selection rules [34].…”

Section: S T O K E S S H I F T ( C M -1 )supporting

confidence: 84%

Raman scattering study of delafossite magnetoelectric multiferroic compounds: CuFeO₂and CuCrO₂

Aktas

Truong

Otani³

et al. 2011

J. Phys.: Condens. Matter

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Ultrasonic velocity measurements on the magnetoelectric multiferroic compound CuFeO2 reveal that the antiferromagnetic transition observed at TN1 = 14 K might be induced by an R3m C2/m pseudoproper ferroelastic transition [1]. In that case, the group theory states that the order parameter associated with the structural transition must belong to a two dimensional irreducible representation Eg (x 2 − y 2 , xy). Since this type of transition can be driven by a Raman Eg mode, we performed Raman scattering measurements on CuFeO2 between 5 K and 290 K. Considering that the isostructural multiferroic compound CuCrO2 might show similar structural deformations at the antiferromagnetic transition TN1 = 24.3 K, Raman measurements have also been performed for comparison. At ambient temperature, the Raman modes in CuFeO2 are observed at ωE g = 352 cm −1 and ωA g = 692 cm −1 , while these modes are detected at ωE g = 457 cm −1 and ωA g = 709 cm −1 in CuCrO2. The analysis of the temperature dependence of modes shows that the frequency of all modes increases down to 5 K. This typical behavior can be attributed to anharmonic phonon-phonon interactions. These results clearly indicate that none of the Raman active modes observed in CuFeO2 and CuCrO2 drive the pseudoproper ferroelastic transition observed at the Néel temperature TN1. Finally, a broad band at about 550 cm −1 observed in the magnetoelectric phase of CuCrO2 below TN2 could be attributed to a magnon mode.

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Section: S T O K E S S H I F T ( C M -1 )supporting

confidence: 84%

Raman scattering study of delafossite magnetoelectric multiferroic compounds: CuFeO₂and CuCrO₂

Aktas

Truong

Otani³

et al. 2011

J. Phys.: Condens. Matter

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“…Based on splitting of the E g mode, authors reported a structural phase transition in the compound beyond 26 GPa. Raman measurements on single crystal of CuAlO 2 up to 48 GPa indicated a pressure driven phase transition at around 34 (±2) GPa, which is completed by 37 (±2) GPa [48]. Raman data on the pressure cycled sample showed the presence of two modes as observed in the ambient sample, indicating the reversibility of the phase transition.…”

Section: High Pressure Studiesmentioning

confidence: 77%

Copper Delafossites under High Pressure—A Brief Review of XRD and Raman Spectroscopic Studies

Garg

Rao

2018

Crystals

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Delafossites, with a unique combination of electrical conductivity and optical transparency constitute an important class of materials with their wide range of applications in different fields. In this article, we review the high pressure studies on copper based semiconducting delafossites with special emphasis on their structural and vibrational properties by synchrotron based powder X-ray diffraction and Raman spectroscopic measurements. Though all the investigated compounds undergo pressure induced structural phase transition, the structure of high pressure phase has been reported only for CuFeO 2 . Based on X-ray diffraction data, one of the common features observed in all the studied compounds is the anisotropic compression of cell parameters in ambient rhombohedral structure. Ambient pressure bulk modulus obtained by fitting the pressure volume data lies between 135 to 200 GPa. Two allowed Raman mode frequencies E g and A 1g are observed in all the compounds in ambient phase with splitting of E g mode at the transition except for CuCrO 2 where along with splitting of E g mode, A 1g mode disappears and a strong mode appears which softens with pressure. Observed transition pressure scales exponentially with radii of trivalent cation being lowest for CuLaO 2 and highest for CuAlO 2 . The present review will help materials researchers to have an overview of the subject and reviewed results are relevant for fundamental science as well as possessing potential technological applications in synthesis of new materials with tailored physical properties.

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“…2 ). 21 The appearance of both modes in the backscatter geometry is due to the polycrystalline nature of the samples examined. With the micro-Raman system used in this study, individual crystallites could be examined across the various different materials.…”

Section: Raman Spectramentioning

confidence: 99%

“…Only the A 1g and E g modes are Raman active. 21,22 Room temperature Raman spectra acquired using a 488 nm laser, shown in Fig. 2 ).…”

Section: Raman Spectramentioning

confidence: 99%

“…The increase in the intensity of the E g mode seen in some crystallites therefore indicates that the orientation of the crystal being examined at least partially satised the selection rule for this mode. 21 Specically, observation of the E g mode in Raman requires that the c-axis of the crystal under examination must not be parallel to the incident beam, and this condition is satised to varying degrees by different crystals. Given that the orientation of the crystal with respect to the incident laser could be identied by the intensity of the E g mode and that the peak located at 236.5 cm À1 was strongly suppressed in orientations where the E g mode scattering is strong, it appears that the peak at 236.5 cm À1 has an angle-dependent scattering cross-section.…”

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confidence: 99%

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The luminescent properties of CuAlO₂

et al. 2014

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aIn this work we examine the room temperature photoluminescence, Raman and low temperature photoluminescence properties of CuAlO 2 prepared using different precursors. At room temperatures the luminescence associated with bulk CuAlO 2 occurs at 355 nm and is associated with strong resonant Raman effects. At low temperatures we find that the UV emission is dominated by strong electronphonon coupling leading to a Franck-Condon type emission band. A second strongly phonon coupled band is also observed in the blue spectral region. In addition we also show that at low temperatures the luminescent properties of CuAlO 2 are meta-stable, with anomalous temperature dependence. The possible origins of the blue band, the meta-stability and anomalous temperature dependence are discussed.

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Pressure and temperature dependence of the lattice dynamics ofCuAlO2investigated by Raman scattering experiments andab initiocalculations

Cited by 96 publications

References 32 publications

Raman scattering study of delafossite magnetoelectric multiferroic compounds: CuFeO₂and CuCrO₂

Raman scattering study of delafossite magnetoelectric multiferroic compounds: CuFeO₂and CuCrO₂

Copper Delafossites under High Pressure—A Brief Review of XRD and Raman Spectroscopic Studies

The luminescent properties of CuAlO₂

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Pressure and temperature dependence of the lattice dynamics ofCuAlO2investigated by Raman scattering experiments andab initiocalculations

Cited by 96 publications

References 32 publications

Raman scattering study of delafossite magnetoelectric multiferroic compounds: CuFeO2and CuCrO2

Raman scattering study of delafossite magnetoelectric multiferroic compounds: CuFeO2and CuCrO2

Copper Delafossites under High Pressure—A Brief Review of XRD and Raman Spectroscopic Studies

The luminescent properties of CuAlO2

Contact Info

Product

Resources

About

Raman scattering study of delafossite magnetoelectric multiferroic compounds: CuFeO₂and CuCrO₂

Raman scattering study of delafossite magnetoelectric multiferroic compounds: CuFeO₂and CuCrO₂

The luminescent properties of CuAlO₂