Lattice dynamics of orthorhombic perovskite YMnO3

Gupta, H.C.; Ashdhir, P.

doi:10.1016/s0921-4526(98)00661-9

Cited by 12 publications

(6 citation statements)

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“…In the orthorhombic perovskite structure, a rigid network is formed from the linkage of MnO 6 octahedra where Mn-O bonds are relatively short and strong. 7) The perovskitetype manganites have been investigated extensively since the late rediscovery of colossal magnetoresistance (CMR) phenomena in doped LaMnO 3 . 8) The factor is 1 for the ideal perovskite structure and becomes smaller as the average ionic radius of the R 3+ ions is reduced and the lattice becomes more distorted.…”

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confidence: 99%

Study on the Electronic Structure of Hexagonal and Orthorhombic YMnO₃

Kwun

Yoon

2000

J. Phys. Soc. Jpn.

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Optical study has revealed the variation of the electronic structures of the covalent Mn-O network in the orthorhombic RMnO 3 compounds. 8) The absorption coefficient (α) was calculated from transmittance and reflectance measurements as a function of incident photon energy (hν). 11) The plot of α 2 versus hν is shown in Fig. 1 since α 2 rather than α varied linearly with hν in the high energy region of the absorption edge. A straight line behavior of the α 2 versus hν plot in the high energy region was taken as the prime evidence for a direct band gap, although low-lying broad tails made it difficult to estimate an accurate value for the band gap energy. The band gap energies of about 4.2 and 4.3 eV were determined for oand h-YMnO 3 , respectively, by extrapolating the linear portion of the plot to α 2 = 0, as shown in Fig. 1.In the low energy region below the absorption edge, the absorption spectrum deviated from the straight line plot. There may be two possible types of transition due to the 3d 4 electronic configuration of the Mn 3+ ion: dd transitions and charge transfer excitations from the valence bands to the Mn 3d level. 12) A low-lying broad peak occurred around 1.6 eV for h-YMnO 3 . The spectra are attributed to d-d electronic transitions within the Mn 3+ ions. 4) On the other hand, the spectrum consisted of two charge transfer type transitions around 3 and 4 eV for o-YMnO 3 , which was similar to the spectrum of LaMnO 3 . 8) X-ray photoelectron spectroscopy (XPS) is a powerful technique which allows the deduction of chemical bonding information for a given compound. The narrow-scan XPS core level spectra of Mn 2p, Y 3d, and O 1s of the two YMnO 3 phases are shown in Figs. 2, 3, and 4, respectively. The x-ray photoelectron spectra were recorded using an Al Kα x-ray source (1486.6 eV). Binding energy was calibrated with reference to C 1s (284.6 eV).Before Ar + sputtering, the Mn 2p 3/2 peak of h-YMnO 3 was at 641.18 eV in Fig. 2(a), which was at 642.05 eV for MnO 2 and at 641.5 eV for Mn 2 O 3 . 13,14) The chemical shift of the Mn 2p 3/2 peak of o-YMnO 3 was 0.3 eV with respect to h-YMnO 3 in Fig. 2(a). On the other hand, the Y 3d 5/2 peaks for the two YMnO 3 phases were at

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confidence: 99%

Study on the Electronic Structure of Hexagonal and Orthorhombic YMnO₃

Kwun

Yoon

2000

J. Phys. Soc. Jpn.

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“…Переход в параэлектрическую фазу протекает при T C ≈ 900 K, а антиферромагнитное (АФМ) упорядочение возникает ниже температуры T N ≈ 80 K [7,8]. Перовскитная Orth-фаза (пространственная группа симметрии Pnma [9]), образующаяся при высоких давлениях и температурах, не является устойчивойповторный отжиг без приложения давления переводит к образованию Hex-фазы [10]. Однако в твердых растворах (ТР) на основе YMnO 3 орторомбическая фаза достаточно устойчива, хотя и формируется часто " в паре" с гексагональной [11].…”

Section: Introductionunclassified

Структура, зеренное строение и диэлектрические свойства керамик твердых растворов YCu-=SUB=-x-=/SUB=-Mn-=SUB=-1-x-=/SUB=-O-=SUB=-3-=/SUB=-

Nazarenko¹,

Pavlenko²,

Абдулвахидов³

2021

Физика Твердого Тела

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Solid solution ceramics of the YCuxMn1-xO3 system at x = 0.05; 0.10; 0.15 were prepared by solid-phase reactions followed by sintering using conventional ceramic technology. The study of their structure, microstructure and dielectric properties including of temperature and frequencies investigation of dielectric permittivity, conductivity and tangent of dielectric loses is carried out. It is established that hexagonal phase is predominantly formed in the ceramics. Its grain structure is unhomogenius, while synthesis is performed with the formation of liquid phases of eutectic origin. It is shown that anomalous behavior of dielectric characteristics at Т=30-200 ºС connected to interlayer polarization effects, while features at Т = 222 ºС (x = 0.05), 234 ºС (x = 0.10) and 247 ºС (x = 0.15) we connected to “isostructural” phase transition that is intermediate between the ferroelectric and paraelectric phases.

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“…Furthermore, several studies have presented the results of experimental measurements of IR and Raman spectra at room temperatures [7][8][9][10], as well as the calculations of dispersive curves and phonon densities of states with the use of empirical methods for the description of interatomic forces [10,11]. However, the existing calculations of the lattice dynamics have been carried out only for the high-temperature Pnma structure.…”

Section: Introductionmentioning

confidence: 99%

Influence of magnetic order on phonon spectra of multiferroic orthorhombic YMnO3

Nikolaev

Mazurenko

Руденко

2013

Solid State Communications

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a b s t r a c tWe perform a first-principles study of lattice dynamics in the low-temperature P2 1 nm phase of orthorhombic YMnO 3 . By considering several possible antiferromagnetic types, we show how magnetic ordering of the system affects its vibrational properties. We find that the experimentally observed magnetic E-type corresponds to the most energetically favorable state and yields phonon spectra, which are consistent with experimental observations. The influence of on-site Coulomb correlations on phonon spectra is also examined. Such effects produce noticeable changes in the spectra and provide a step toward a more accurate description of lattice dynamics in YMnO 3 .

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Lattice dynamics of orthorhombic perovskite YMnO3

Cited by 12 publications

References 5 publications

Study on the Electronic Structure of Hexagonal and Orthorhombic YMnO₃

Study on the Electronic Structure of Hexagonal and Orthorhombic YMnO₃

Структура, зеренное строение и диэлектрические свойства керамик твердых растворов YCu-=SUB=-x-=/SUB=-Mn-=SUB=-1-x-=/SUB=-O-=SUB=-3-=/SUB=-

Influence of magnetic order on phonon spectra of multiferroic orthorhombic YMnO3

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Lattice dynamics of orthorhombic perovskite YMnO3

Cited by 12 publications

References 5 publications

Study on the Electronic Structure of Hexagonal and Orthorhombic YMnO3

Study on the Electronic Structure of Hexagonal and Orthorhombic YMnO3

Структура, зеренное строение и диэлектрические свойства керамик твердых растворов YCu-=SUB=-x-=/SUB=-Mn-=SUB=-1-x-=/SUB=-O-=SUB=-3-=/SUB=-

Influence of magnetic order on phonon spectra of multiferroic orthorhombic YMnO3

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Study on the Electronic Structure of Hexagonal and Orthorhombic YMnO₃

Study on the Electronic Structure of Hexagonal and Orthorhombic YMnO₃