Twinning in Ti<sub>4</sub>O<sub>7</sub>

Hodeau, Jean-Louis; Marezio, M.; Schlenker, C.; Buder, R.; Lakkis, S.

doi:10.1107/s0021889876011680

Cited by 13 publications

(7 citation statements)

References 4 publications

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“…This explanation, however, invariably led to the conclusion that order parameter strain coupling is important for the phase transitions of T4O7. Grown single crystals are known to be twinned (Hodeau et al, 1976). According to thls Inglis et al (1983) explain irreversible changes in the conductivity by a deterioration of the samples associated with the 'virgin' twinning and the structural deformation (volume expansion) at the 150 K transition.…”

Section: Discussionmentioning

confidence: 98%

X-Ray powder diffraction study of the phase transitions in Ti₄O₇

Melzer¹,

Rüscher²

1996

Phase Transitions

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A high precision temperature dependent X-ray powder diffraction study has been carried out on Ti407 in the temperature range between 180 and 90 K enclosing the metal-insulator and the so-called Ti407-Verwey transition. Both transitions are characterized by negative volume effects as can be deduced from the temperature dependent course of the lattice parameters. Total strains induced by the formation of the intermediate phase are about 0.007 and about twice that value in the low temperature phase. In successive heating and cooling runs it is observed that the low temperature transition occurs stepwise, possibly related to the deterioration of the modulated structure.

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Section: Discussionmentioning

confidence: 98%

X-Ray powder diffraction study of the phase transitions in Ti₄O₇

Melzer¹,

Rüscher²

1996

Phase Transitions

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“…The indexing led to an f.c.c, space group; however, there were intermittent diffuse-scattering streaks parallel to the {100} directions of the cubic cell (air × air × air). In a previous paper (Hodeau, Marezio & Remeika, 1984) the presence of such diffuse streaks was interpreted qualitatively as due to a disorder between the M(2) and Sn(2) atoms. 1 that they form intermittent squares centered around the cubic lattice nodes.…”

Section: X-ray Measurementsmentioning

confidence: 91%

“…The results proved that phases II and II' had related structures and the same chemical formulae. Phase I' compounds have a slightly distorted phase I structure; its symmetry is either cubic with a~, = 2a~ or tetragonal with ai,=a~2 ~/2 and ci,=a~ (Hodeau, Marezio, Remeika & Chen, 1982;Miraglia, Hodeau, Marezio, Laviron, Ghedira & Espinosa, 1986 (2)4Sn(3)12Sn(4)2 (Hodeau, Marezio & Remeika, 1984). The diffuse streaks are lines parallel to the {100} cubic (a~i,x an,× an,) directions and going through the F-centering-forbidden nodes.…”

mentioning

confidence: 99%

Structural studies by electron and X-ray diffraction of the disordered phases II': (Sn_1−xTb_x)Tb₄Rh₆Sn₁₈ and (Sn_1−xDy_x)Dy₄Os₆Sn₁₈

Miraglia¹,

Hodeau²,

Bergevin³

et al. 1987

Acta Crystallogr Sect B

Self Cite

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Snl_xTbx)Tb4Rh6Sn18 and (Snl_xDyx)Dy4OsrSnls belong to a large stannide series where there exist two chemical formulae: SnM3M~Sn~2 (phase I and I') and SnM4M~Sn~8 (phase II and II'), and four structures: I, I', II and II'. That of phase II' appeared to be cubic (a = 13.7/~ and space group Fm3m) while the structure of phase II is tetragonal (a = 13-7, c ~-27.4A and space group I4~/acd). Phase II' of the * Present address: KFK, ITP Postfach 3640, D-7500 Karlsruhe, Federal Republic of Germany. 0108-7681/87/010076-08501.50 streaks. Crystal data for (Snl_xTb,,)Tb4Rh6Snl8, x = 1: M, = 3548.5, disordered microtwinned tetra~onal, 14~/acd, a = 13.772 (2)A, c=2a, V= 5224.2 A, Z= 8, D,, = 9.02 gcm -3, Ag Ka, graphite monochromator, /z = 175-9 cm -t, F(000) = 11 960, T= ambient. AbstractElectron-density distribution of a nitrite ion was calculated by the ab initio molecular-orbital method using STO-3G, STO-6G, MIDI4 and MIDI4* basis sets. The N-O bonding peak, which was observed in the experimental deformation density of LiNO2.H20, could be reproduced only by using the MIDI4* basis set. This indicates the importance of polarization functions in the study of charge distribution.

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“…We use Troullier-Martins pseudopotentials 29 and double-ζ basis sets with polarization functions for Ti and O atoms. Ti 4 O 7 has a triclinic structure with two pseudo-orthorhombic sublattices 30 . Each unit cell consists of two formula units with a total of 22 atoms (Fig.…”

Section: Methodsmentioning

confidence: 99%

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

et al. 2015

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Understanding electronic properties of sub-stoichiometric phases of titanium oxide such as Magnéli phase Ti 4 O 7 is crucial in designing and modeling resistive switching devices. Here we present our study on Magnéli phase Ti 4 O 7 together with rutile TiO 2 and Ti 2 O 3 using density functional theory methods with atomic-orbital-based self-interaction correction (ASIC). We predict a new antiferromagnetic ground state in the low temperature phase (or LT phase), and we explain energy difference with a competing antiferromagnetic state using a Heisenberg model. The predicted energy ordering of these states in the LT phase is calculated to be robust in a wide range of modeled isotropic strain. We have also investigated the dependence of the electronic structures of the Ti-O phases on stoichiometry. The splitting of titanium t 2g orbitals is enhanced with increasing oxygen deficiency as Ti-O is reduced. The electronic properties of all these phases can be reasonably well described by applying ASIC with a 'standard' value for transition metal oxides of the empirical parameter α of 0.5 representing the magnitude of the applied self-interaction correction.

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Twinning in Ti₄O₇

Abstract: Twinning has been studied in Ti407 crystals. It has been found that they are twinned by reticular pseudomerohedry. The sublattice controlling the twinning has an orthorhombic pseudosymmetry and is obtained from the triclinic cell (

Cited by 13 publications

References 4 publications

X-Ray powder diffraction study of the phase transitions in Ti₄O₇

X-Ray powder diffraction study of the phase transitions in Ti₄O₇

Structural studies by electron and X-ray diffraction of the disordered phases II': (Sn_1−xTb_x)Tb₄Rh₆Sn₁₈ and (Sn_1−xDy_x)Dy₄Os₆Sn₁₈

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

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Twinning in Ti4O7

Abstract: Twinning has been studied in Ti407 crystals. It has been found that they are twinned by reticular pseudomerohedry. The sublattice controlling the twinning has an orthorhombic pseudosymmetry and is obtained from the triclinic cell (

Cited by 13 publications

References 4 publications

X-Ray powder diffraction study of the phase transitions in Ti4O7

X-Ray powder diffraction study of the phase transitions in Ti4O7

Structural studies by electron and X-ray diffraction of the disordered phases II': (Sn1−x Tb x )Tb4Rh6Sn18 and (Sn1−x Dy x )Dy4Os6Sn18

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

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About

Twinning in Ti₄O₇

X-Ray powder diffraction study of the phase transitions in Ti₄O₇

X-Ray powder diffraction study of the phase transitions in Ti₄O₇

Structural studies by electron and X-ray diffraction of the disordered phases II': (Sn_1−xTb_x)Tb₄Rh₆Sn₁₈ and (Sn_1−xDy_x)Dy₄Os₆Sn₁₈