Post-spinel transformations and equation of state in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>ZnGa</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>: Determination at high pressure by<i>in situ</i>x-ray diffraction

Errandonea, Daniel; Kumar, Ravhi S.; Manjón, F. J.; Ursaki, V. V.; Rusu, E.

doi:10.1103/physrevb.79.024103

Cited by 79 publications

(42 citation statements)

References 36 publications

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“…No evidence of phase transition is found up to 13 GPa. Even the tetragonal distortion of the cubic spinel structure, observed in other spinels under compression, 9 is not observed in our experiments. This fact contradicts the conclusions extracted from resistivity measurements.…”

Section: A Sample Characterizationcontrasting

confidence: 43%

“…11 This fact is in contradiction with the results reported for spinel ZnGa 2 O 4 for which the compression of the cubic and tetragonal polymorphs can be described with the same equation of state (EOS). 9 On top of that, HP resistivity experiments carried out in CoFe 2 O 4 nanocrystals indicated that the phase transition to the post-spinel structure occurs at 7.5 and 12 GPa for 80 and 6 nm particles, respectively. 12 The reduction of the transition pressure from 20 GPa to less than 12 GPa was explained as a consequence of the transformation of CoFe 2 O 4 into a metastable phase that does not exist in the bulk material.…”

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confidence: 99%

“…5 After Finger et al 6 studied the structure of spinel and magnetite under compression up to 4 GPa, spinel-type oxides have been the focus of high-pressure (HP) studies. 2,5,[7][8][9][10] In particular, HP x-ray diffraction (XRD) experiments have been performed recently to study the crystal structure of cobalt ferrite. 5,7 It has been reported that the onset of a phase transition to a post-spinel structure takes place at around 20-27 GPa.…”

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confidence: 99%

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Cobalt ferrite nanoparticles under high pressure

Saccone

Ferrari

Errandonea

et al. 2015

Journal of Applied Physics

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Articles you may be interested inMicrostructure and magnetic properties of MFe2O4 (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method J. Appl. Phys. 117, 17A328 (2015) We report by the first time a high pressure X-ray diffraction and Raman spectroscopy study of cobalt ferrite (CoFe 2 O 4 ) nanoparticles carried out at room temperature up to 17 GPa. In contrast with previous studies of nanoparticles, which proposed the transition pressure to be reduced from 20-27 GPa to 7.5-12.5 GPa (depending on particle size), we found that cobalt ferrite nanoparticles remain in the spinel structure up to the highest pressure covered by our experiments. In addition, we report the pressure dependence of the unit-cell parameter and Raman modes of the studied sample. We found that under quasi-hydrostatic conditions, the bulk modulus of the nanoparticles (B 0 ¼ 204 GPa) is considerably larger than the value previously reported for bulk CoFe 2 O 4 (B 0 ¼ 172 GPa). In addition, when the pressure medium becomes non-hydrostatic and deviatoric stresses affect the experiments, there is a noticeable decrease of the compressibility of the studied sample (B 0 ¼ 284 GPa). After decompression, the cobalt ferrite lattice parameter does not revert to its initial value, evidencing a unit cell contraction after pressure was removed. Finally, Raman spectroscopy provides information on the pressure dependence of all Raman-active modes and evidences that cation inversion is enhanced by pressure under non-hydrostatic conditions, being this effect not fully reversible. V C 2015 AIP Publishing LLC. [http://dx

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Section: A Sample Characterizationcontrasting

confidence: 43%

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confidence: 99%

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confidence: 99%

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Cobalt ferrite nanoparticles under high pressure

Saccone

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Errandonea

et al. 2015

Journal of Applied Physics

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“…Among other techniques, they have been studied by XRD, being several pressure-induced transitions reported. [6][7][8][9][10][11][12][13][14][15] The reversibility of these transitions is subject of dispute. In some cases, it has been found that the transitions are not reversible, being metastable polymorphs recovered at ambient conditions after decompression.…”

Section: Introductionmentioning

confidence: 99%

X-ray diffraction study on pressure-induced phase transformations and the equation of state of ZnGa2Te4

Errandonea

Kumar

Gomis

et al. 2013

Journal of Applied Physics

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We report on high-pressure x-ray diffraction measurements up to 19.8 GPa in zinc digallium telluride (ZnGa 2 Te 4 ) at room temperature. An irreversible structural phase transition takes place at pressures above 12.1 GPa and upon decompression a third polymorph of ZnGa 2 Te 4 was recovered as a metastable phase at pressures below 2.9 GPa. Rietveld refinements were carried out for the three detected polymorphs, being their possible crystal structures reported. The axial compressibilities for the low-pressure phase of ZnGa 2 Te 4 have been determined as well as the equation of state of the low-and high-pressure phases. The reported results are compared with those available in the literature for related compounds. Pressure-induced coordination changes and transition mechanisms are also discussed. V C 2013 AIP Publishing LLC. [http://dx

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“…To check if we can recover this transition from our theory, we carried out calculations within GGA+U+SO at different pressures. At this point, we would like to mention that certain cubic spinels such as ZnGa 2 O 4 [21] are observed to undergo cubic to tetragonal structural transition under pressure. Since no experimental information is available in literature about the distortions introduced by application of pressure on cubic spinel CoV 2 O 4 , it is worth exploring the possibility of a cubic to tetragonal transition in this system on increasing the pressure.…”

Section: Gga+u+so: Transport Properties Under Pressurementioning

confidence: 99%

The nature of itineracy in CoV₂O₄: a first-principles study

Kaur¹,

Maitra²,

Nautiyal³

2014

J. Phys.: Condens. Matter

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Abstract. Inspired by recent experiments, we have theoretically explored the nature of itineracy in CoV 2 O 4 under pressure and investigated, using first principles density functional theory calculations, if it has any magnetic and orbital ordering. Our calculations indicate that there could be two possible routes to obtain the experimentally observed pressure induced metallicity in this system. One is the spinorbit interaction coupled with Coulomb correlation which can take the system from a semiconducting state at ambient pressure to a metallic state under high pressure. The other mechanism, as indicated by our GGA+U calculations, is based on the presence of two types of electrons in the system: localized and itinerant. An effective FalicovKimball model could then possibly explain the observed insulator to metal transition. Comparison of the two scenarios with existing experimental observations leads us to believe that the second scenario offers a better explanation for the mechanism of insulator to metal transition in CoV 2 O 4 under pressure.

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Post-spinel transformations and equation of state inZnGa2O4: Determination at high pressure byin situx-ray diffraction

Abstract: Room temperature angle-dispersive x-ray diffraction measurements on spinel

Cited by 79 publications

References 36 publications

Cobalt ferrite nanoparticles under high pressure

Cobalt ferrite nanoparticles under high pressure

X-ray diffraction study on pressure-induced phase transformations and the equation of state of ZnGa2Te4

The nature of itineracy in CoV₂O₄: a first-principles study

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Post-spinel transformations and equation of state inZnGa2O4: Determination at high pressure byin situx-ray diffraction

Abstract: Room temperature angle-dispersive x-ray diffraction measurements on spinel

Cited by 79 publications

References 36 publications

Cobalt ferrite nanoparticles under high pressure

Cobalt ferrite nanoparticles under high pressure

X-ray diffraction study on pressure-induced phase transformations and the equation of state of ZnGa2Te4

The nature of itineracy in CoV2O4: a first-principles study

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Product

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The nature of itineracy in CoV₂O₄: a first-principles study