Anharmonic behavior and structural phase transition in Yb2O3

Abstract

The investigation of structural phase transition and anharmonic behavior of Yb2O3 has been carried out by high-pressure and temperature dependent Raman scattering studies respectively. In situ Raman studies under high pressure were carried out in a diamond anvil cell at room temperature which indicate a structural transition from cubic to hexagonal phase at and above 20.6 GPa. In the decompression cycle, Yb2O3 retained its high pressure phase. We have observed a Stark line in the Raman spectra at 337.5 cm−1 which arises from the electronic transition between 2F5/2 and 2F7/2 multiplates of Yb3+ (4f13) levels. These were followed by temperature dependent Raman studies in the range of 80–440 K, which show an unusual mode hardening with increasing temperature. The hardening of the most dominant mode (Tg + Ag) was analyzed in light of the theory of anharmonic phonon-phonon interaction and thermal expansion of the lattice. Using the mode Grüneisen parameter obtained from high pressure Raman measurements; we have calculated total anharmonicity of the Tg + Ag mode from the temperature dependent Raman data.

Investigations of anharmonic effects via phonon mode variations in nanocrystalline Dy2O3, Gd2O3 and Y2O3

“…Among these, the anharmonic effects in Ho 2 O 3 and Yb 2 O 3 have already been reported elsewhere. [22,23] The present report investigates the temperature-dependent behaviour of Dy 2 O 3 , Gd 2 O 3 and Y 2 O 3 . We have investigated the temperature-dependent variation in phonon modes and associated peak widths to elucidate the mechanisms predominantly driving the wavenumber shifts, phonon lifetimes, and so on.…”

“…Hence, in recent past, we have been investigating the temperature‐dependent phonon variation in nanosized rare earth sesquioxides. Among these, the anharmonic effects in Ho 2 O 3 and Yb 2 O 3 have already been reported elsewhere . The present report investigates the temperature‐dependent behaviour of Dy 2 O 3 , Gd 2 O 3 and Y 2 O 3 .…”

Structural properties and the pressure-induced C → A phase transition of lanthanide sesquioxides from DFT and DFT + U calculations

“…In some cases, evidence of a direct C→A transition was recently observed for the first time [13,18,19]. In this respect, XRD and also Raman scattering experiments allowed the study of the C to A transition induced by high pressure under static load [15][16][17][18][19][20][21][22][23][24] or shock compression [25].…”

Structural phase transition of ternary dielectric SmGdO3: Evidence from angle dispersive x-ray diffraction and Raman spectroscopic studies

“…Furthermore, the exotic and rich physical properties of these oxides could be tuned by external pressure and temperature, which induce significant crystallographic and electronic changes. [5][6][7] Recently, some of the rare-earth sesquioxides (REOs) have attracted considerable attention as high-k dielectric materials in order to replace the conventional gate dielectric material, silicon dioxide, in complementary metal-oxide semiconductor (CMOS) technology. [8][9][10] Interestingly, some of REOs were found to possess variable dielectric constant depending on their crystal structure.…”