Discovery of high-pressure post-perovskite phase in HoCrO3

Mall, Ashish Kumar; Garg, Nandini; Verma, Ashok; Errandonea, Daniel; Chitnis, Abhishek; Srihari, Velaga; Gupta, Rajeev

doi:10.1016/j.jpcs.2022.111078

Cited by 5 publications

(5 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pseudo-cubic lattice parameter

(parallel to the long Pr–O bonds in the

polyhedral unit) is more compressible (

2.72

) than both

(

0.18

) and

(

0.92

). These values are similar to the anisotropic compressibility reported for

[ 58 ], and similarly for

and

[ 59 ], and

[ 60 ]. However, while the a -axis (in the

setting) for

was also found to be significantly more compressible than the other axes, the b -axis expanded slightly under pressure [ 22 ].…”

Section: Resultssupporting

confidence: 88%

“…The value of

230.12 3

is very close to that extracted from refinement of ambient pressure diffraction data ( table 1 ). The value of

is significantly different to that calculated from density functional theory [ 61 ], though in good agreement with the experimental trend of values from other rare-earth orthochromites [ 22 , 58 – 60 , 62 ]. The negative curvature (

) of the volume–pressure curve is not seen in the other rare-earth orthochromites, suggesting that the material abnormally softens with pressure.…”

Section: Resultssupporting

confidence: 67%

“…There are very few high-pressure structural studies on the lanthanide orthochromites in the literature, with the majority of them being X-ray diffraction studies, only reporting the changes in lattice parameters [22,58–60]. A neutron study of LaCrO3 showed that it was found to change from orthorhombic to rhombohedral symmetry at approximately 5 GPa [62,71,72].…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

A structural study of PrCrO ₃ under extreme conditions: a comparison with the effects of doping

Bull,

Funnell,

Ridley

2023

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

The nuclear and magnetic structure of PrCrO 3 has been investigated using neutron and X-ray powder diffraction as a function of pressure and temperature. The orthorhombic symmetry (space group P b n m ) remains stable up to the highest temperature (1500 K) and pressure (approx. 6 GPa ) considered. There is a crossover in the magnitude of the a- and b -lattice parameters at approximately 1135 K, caused by competing effects of octahedral tilting and distortion. The material is antiferromagnetic ( T N ≈ 240 K) with P b ′ n ′ m symmetry, with a maximum moment of 2.34 ( 2 ) μ b on the Cr 3 + sites aligned along the direction of the a -axis. The application of pressure shows an abnormal softening in the unit-cell volume, which is suggestive of a continuous approach to a second-order phase transition. Raman spectroscopy measurements at ambient temperature were collected as a function of pressure up to approximately 12 GPa, with discontinuous mode behaviour further suggesting the existence of a transition above 7 GPa. The measured structural changes in PrCrO 3 are compared extensively in the wider context of other lanthanide orthochromites, and the comparative effects of A - and B -site substitution on the polyhedral tilts and distortion are discussed. This article is part of the theme issue ‘Exploring the length scales, timescales and chemistry of challenging materials (Part 1)’.

show abstract

“…The pseudo-cubic lattice parameter

(parallel to the long Pr–O bonds in the

polyhedral unit) is more compressible (

2.72

) than both

(

0.18

) and

(

0.92

). These values are similar to the anisotropic compressibility reported for

[ 58 ], and similarly for

and

[ 59 ], and

[ 60 ]. However, while the a -axis (in the

setting) for

was also found to be significantly more compressible than the other axes, the b -axis expanded slightly under pressure [ 22 ].…”

Section: Resultssupporting

confidence: 88%

“…The value of

230.12 3

is very close to that extracted from refinement of ambient pressure diffraction data ( table 1 ). The value of

) of the volume–pressure curve is not seen in the other rare-earth orthochromites, suggesting that the material abnormally softens with pressure.…”

Section: Resultssupporting

confidence: 67%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

A structural study of PrCrO ₃ under extreme conditions: a comparison with the effects of doping

Bull,

Funnell,

Ridley

2023

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

show abstract

“…The existence of the phase transition was postulated to explain changes in the intensity of Raman modes and the broadening of internal modes . One possibility to explain this apparent discrepancy is the presence of different non-hydrostatic conditions in experiments . However, our pressure medium (16:3:1 methanol–ethanol–water) provides a similar high-pressure environment to 4:1 methanol–ethanol .…”

Section: Resultsmentioning

confidence: 99%

“…20 One possibility to explain this apparent discrepancy is the presence of different non-hydrostatic conditions in experiments. 49 However, our pressure medium (16:3:1 methanol−ethanol−water) provides a similar high-pressure environment to 4:1 methanol− ethanol. 50 A more plausible explanation would be the bridging of the sample between diamonds, which could have strongly influenced the results of high-pressure studies.…”

Section: ■ Methodsmentioning

confidence: 99%

Equations of State and Crystal Structures of KCaPO₄, KSrPO₄, and K₂Ce(PO₄)₂ under High Pressure: Discovery of a New Polymorph of KCaPO₄

Errandonea

Achary

Díaz-Anichtchenko

et al. 2023

Crystal Growth & Design

Self Cite

View full text Add to dashboard Cite

We have studied by means of angle-dispersive powder synchrotron X-ray diffraction the structural behavior of KCaPO 4 , SrKPO 4 , and K 2 Ce(PO 4 ) 2 under high pressure up to 26, 25, and 22 GPa, respectively. For KCaPO 4 , we have also accurately determined the crystal structure under ambient conditions, which differs from the structure previously reported. Arguments supporting our structural determination will be discussed. We have found that KCaPO 4 undergoes a reversible phase transition. The onset of the transition is at 5.6 GPa. It involves a symmetry decrease. The low-pressure phase is described by space group P3̅ m1 and the high-pressure phase by space group Pnma. For KSrPO 4 and K 2 Ce(PO 4 ) 2 , no evidence of phase transitions has been found up to the highest pressure covered by the experiments. For the three compounds, the linear compressibility for the different crystallographic axes and the pressure−volume equation of states are reported and compared with those of other phosphates. The three studied compounds are among the most compressible phosphates. The results of the study improve the knowledge about the high-pressure behavior of complex phosphates.

show abstract

High-pressure structural phase transition on Bi14MoO24

Botella

Santamarı́a-Pérez

Otero-de-la-Roza

et al. 2023

Journal of Physics and Chemistry of Solids

View full text Add to dashboard Cite

Discovery of high-pressure post-perovskite phase in HoCrO3

Cited by 5 publications

References 70 publications

A structural study of PrCrO ₃ under extreme conditions: a comparison with the effects of doping

A structural study of PrCrO ₃ under extreme conditions: a comparison with the effects of doping

Equations of State and Crystal Structures of KCaPO₄, KSrPO₄, and K₂Ce(PO₄)₂ under High Pressure: Discovery of a New Polymorph of KCaPO₄

High-pressure structural phase transition on Bi14MoO24

Contact Info

Product

Resources

About

Discovery of high-pressure post-perovskite phase in HoCrO3

Cited by 5 publications

References 70 publications

A structural study of PrCrO 3 under extreme conditions: a comparison with the effects of doping

A structural study of PrCrO 3 under extreme conditions: a comparison with the effects of doping

Equations of State and Crystal Structures of KCaPO4, KSrPO4, and K2Ce(PO4)2 under High Pressure: Discovery of a New Polymorph of KCaPO4

High-pressure structural phase transition on Bi14MoO24

Contact Info

Product

Resources

About

A structural study of PrCrO ₃ under extreme conditions: a comparison with the effects of doping

A structural study of PrCrO ₃ under extreme conditions: a comparison with the effects of doping

Equations of State and Crystal Structures of KCaPO₄, KSrPO₄, and K₂Ce(PO₄)₂ under High Pressure: Discovery of a New Polymorph of KCaPO₄