Structural phase transitions of cubic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Gd</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>at high pressures

Zhang, F.X.; Lang, Maik; Wang, J. W.; Becker, Udo; Ewing, Rodney C.

doi:10.1103/physrevb.78.064114

Cited by 119 publications

(70 citation statements)

References 27 publications

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“…7 The B to A or A to B transition requires lesser energy as it is displacive type. In this context, it is relevant to mention here that Zhang et al 29 also reported a phase diagram for Gd 2 O 3 according to which at low temperatures, the cubic to hexagonal phase transition is favored with application of pressure while at high temperatures, the monoclinic phase is favored. Since the kinetics of phase transformation depend in general on the pressure, temperature and the amount of non-hydrostatic stresses as well as the existence of defects; the barrier heights for transformation would also depend on these parameters.…”

Section: Resultsmentioning

confidence: 84%

Anharmonic behavior and structural phase transition in Yb2O3

Pandey¹,

Samanta²,

Singh³

et al. 2013

AIP Advances

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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.

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Section: Resultsmentioning

confidence: 84%

Anharmonic behavior and structural phase transition in Yb2O3

Pandey¹,

Samanta²,

Singh³

et al. 2013

AIP Advances

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“…The P-V data up to 12 GPa were fitted to the Birch-Murnaghan equation of state [19] and the bulk modulus and its pressure derivative were found to be: B 0 = 118 ± 21 GPa and B 0 ' =13.9 ± 7.7 respectively [11]. This value of bulk modulus is smaller compared to the reported values of 164, 134 and 188 GPa [15,17,18] with B 0 ' fixed at 4. These values of the bulk moduli are comparable with those reported for other RE 2 O 3 systems [4,[20][21][22].…”

Section: Resultsmentioning

confidence: 73%

“…A recent study on Er-doped Gd 2 O 3 up to ~40 GPa indicated the C→A transition at 8.57-12.5 GPa [15]. However, it [17,18]. The differences in the phase transition behaviour during the return cycle may be due to the difference in the sample quality and the thermal history.…”

Section: Resultsmentioning

confidence: 99%

High Pressure Structural Studies on Rare-Earth Sesquioxides

Sahu¹,

Lonappan

Shekar

2012

J. Phys.: Conf. Ser.

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High -pressure synchrotron x-ray diffraction study of RMnO 3 (R = Eu, Gd, Tb and Dy) upto 50 GPa D V S Muthu, A E Midgley, P R Scott et al. Abstract. The Rare-Earth sesquioxides (RE 2 O 3 ) exhibit interesting physical and chemical properties. Some of these oxides have tremendous technological applications. At ambient conditions, the RE 2 O 3 systems exist in three polymorphic forms, namely: hexagonal A-type, monoclinic B-type, and cubic C-type. The structural stability of three RE 2 O 3 systems: RE = Gd, Ho, Tm and the Tb 4 O 7 system have been studied under high pressure. All the four systems exhibited interesting pressure induced phase transitions. Gd 2 O 3 exhibited C-A transition at ~ 12 GPa, whereas Ho 2 O 3 and Tm 2 O 3 exhibited C-B transition at pressures of 9.5 and 7 GPa respectively. Tb 4 O 7 transformed from its cubic fluorite structure to probably the cotunnite phase at a relatively higher pressure of 27 GPa. The unusual large pressure stability of Tb 4 O 7 was attributed to the presence of Tb 4+ ions. The bulk moduli show systematic increase with higher cations, probably due to the enhanced influence of the 4f electron states and increased nature of covalency. However, the mechanisms of the structural transitions C-B-A with increased pressure and increased cation radii are yet to be understood.

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“…The dependence of physical properties on the size opens the way for various applications of Gd 2 O 3 nano particles as protective and corrosive resistant coatings, active additives for the low temperature synthesis of ceramics, grain growth inhibitors, and phase stabiliz ers, as well as in optics (antireflective coatings, thin films for ultraviolet lasers), X ray imaging systems, sensors, nuclear engineering, and other fields of sci ence and technology [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Properties of the amorphous-nanocrystalline Gd2O3 powder prepared by pulsed electron beam evaporation

et al. 2013

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Abstract-An amorphous-nanocrystalline Gd 2 O 3 powder with a specific surface area of 155 m 2 /g has been prepared using pulsed electron beam evaporation in vacuum. The nanopowder consists of 20 to 500 nm agglomerates formed by crystalline nanoparticles (3-12 nm in diameter) connected by amorphous-nanoc rystalline strands. At room temperature, the Gd 2 O 3 nanopowder exhibits a paramagnetic behavior. The phase transformations occurring in the powder have been investigated using differential scanning calorimetry and thermogravimetry (40-1400°C). The amorphous phase of the nanopowder is thermally stable up to a tem perature of 1080°C. It has been found that the amorphous phase has an inhibitory effect on the temperature of the polymorphic transformation from the cubic phase into the monoclinic phase. It has been revealed that, compared with the microcrystalline powder, the Gd 2 O 3 nanopowder is characterized by a complete quench ing of photoluminescence.

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Structural phase transitions of cubicGd2O3at high pressures

Cited by 119 publications

References 27 publications

Anharmonic behavior and structural phase transition in Yb2O3

Anharmonic behavior and structural phase transition in Yb2O3

High Pressure Structural Studies on Rare-Earth Sesquioxides

Properties of the amorphous-nanocrystalline Gd2O3 powder prepared by pulsed electron beam evaporation

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