Etude structurale de quatre nouvelles pérovskites au cobalt

Harari, D.; Poix, P.; Bernier, J.C.

doi:10.1016/s0022-4596(74)80038-1

Cited by 29 publications

(16 citation statements)

References 9 publications

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“…Considering two Co 3+ ions per formula unit and, as calculated from the susceptibility measurements and obtained effective magnetic moment, only 40% of them being in a HS state with S = 2, the saturation magnetization should be of the order of 2 × 0.4 gS μ B ≈ 3.2 μ B per formula unit. The measured remanent magnetization of 0.09 μ B /fu at 2 K is much smaller, which is in accordance with the proposed ferrimagnetic ordering of magnetic moments in Sr 3 Co 2 WO 9 …”

Section: Resultssupporting

confidence: 87%

“…The transition temperature T c = 144 K has been determined as a maximum of a negative derivative −dχ/d T of the FC susceptibility obtained in 100 Oe. Even though Harari et al reported ferrimagnetic behavior for Sr 3 Co 2 WO 9 , they did not report the Curie temperature, so we had no referent value to compare it with . The splitting between ZFC and FC susceptibility strongly reduces with increasing magnetic field and almost disappears in a magnetic field of 10 kOe.…”

Section: Resultsmentioning

confidence: 89%

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Rational Sol–Gel-Based Synthesis Design and Magnetic, Dielectric, and Optical Properties Study of Nanocrystalline Sr₃Co₂WO₉ Triple Perovskite

et al. 2020

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Complex perovskites have attracted extensive attention due to their fascinating physical properties and novel features owing to the coexistence of the ferro-/ferri-magnetic ground state and semiconducting behavior in the single material. Herein, the triple perovskite Sr 3 Co 2 WO 9 (SCWO) has been successfully synthesized for the first time in the nanocrystalline form with an average crystallite size of 23 nm using a high yield (81%) aqueous citrate sol−gel method. At room temperature, the crystal structure of Sr 3 Co 2 WO 9 is cubic, space group Fm3̅ m, with lattice parameter a = 7.9073(6) Å. The formation of SCWO triple perovskite was studied in situ by X-ray diffraction and subsequently analyzed by the Rietveld analysis. The detected hysteresis loops with nonzero remanent magnetization and rather large coercive field reveal ferrimagnetic ordering with a Curie temperature of 144 K. The measured effective magnetic moment of 3 μ B is close to the expected value for the rarely observed intermediate spin S = 1. It is found that the compound exhibits semiconducting properties with the optical band gaps equal to 3.52 eV (indirect) and 3.76 eV (direct), respectively, further confirmed by the determination of the AC conductivity, which in the measured temperature range (25−500 °C at 1 kHz) lies within the interval from 10 −5 −10 −4 Ω −1 cm −1 . The Maxwell−Wagner model is employed to describe the frequency dependent dielectric constant. The frequency-dependent AC conductivity follows the universal Jonscher power law. Since it possesses both magnetic and semiconductor properties, this material could be a promising candidate to use in devices where its semiconducting properties would be spin-controlled.

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 89%

Rational Sol–Gel-Based Synthesis Design and Magnetic, Dielectric, and Optical Properties Study of Nanocrystalline Sr₃Co₂WO₉ Triple Perovskite

et al. 2020

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“…These oxides were previously studied in the seventies, and the crystal structures were described in a cubic (Fm3 ¯m) or hexagonal (P6 3 /mmc) lattices, respectively. [10][11][12] Whereas the structure of Sr compound can be described as a three-dimensional network of corner-linked (Fe,Te)O 6 octahedra, the Ba perovskite contains dimer units of face-shared octahedra connected, via common corners, by a single layers of FeO 6 octahedra. In this paper we report on the results of a high resolution NPD study, reexamining the true symmetry and space group of the Sr perovskite and giving a detailed description of both crystal structures as well as thermal evolution down to 2 K for Sr 3 Fe 2 TeO 9 .…”

Section: Introductionmentioning

confidence: 99%

Crystal structure and magnetism of the double perovskites Sr3Fe2TeO9 and Ba3Fe2TeO9: a neutron diffraction study

et al. 2006

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double perovskites have been prepared in polycrystalline form by solid state reaction, in air. These materials have been studied by X-ray diffraction (XRD), neutron powder diffraction (NPD) and magnetic measurements. At room temperature, the crystal structure of Sr 3 Fe 2 TeO 9 is tetragonal, space group I4/m, with a = b = 5.55902(4) A ˚, c = 7.885(1) A ˚, whereas Ba 3 Fe 2 TeO 9 presents a hexagonal lattice, space group P6 3 /mmc, with a = 5.7670(1) A ˚, c = 14.1998(4) A ˚. The structure of Sr 3 Fe 2 TeO 9 , which can ideally be rewritten as Sr 2 Fe(Fe 1/3 Te 2/3 )O 6 , can be described as the result of a single anti-phase tilting of the FeO 6 and (Fe,Te)O 6 octahedra along the c axis, exhibiting a tilting angle of 4.5u at RT. Ba 3 Fe 2 TeO 9 shows a different stacking of the Fe/Te octahedra: the structure is constituted by dimer units of (Fe,Te)O 6 octahedra sharing a face along the c axis; the dimers are connected, sharing corners, by a single layer of FeO 6 octahedra. In both Sr and Ba compounds a certain degree of antisite disordering has been detected, implying the presence of about 15% Te at Fe positions. Magnetic measurements show the onset of ferrimagnetic ordering at relatively high temperatures of 717 and 711 K for the Sr and Ba compounds, respectively; however the magnetization isotherms at 2 K exhibit, for H = 50 kOe, maximum magnetization values close to 0.8 m B f.u. 21 and 0.35 m B f.u. 21 for Sr and Ba compounds respectively, although full saturation is not reached. The extremely weak magnetic scattering contribution observed on the low-temperature NPD patterns for Sr 3 Fe 2 TeO 9 is in contrast with the well-established ferrimagnetic structures observed for other members of the Sr 3 Fe 2 B0O 9 double perovskite series (B0 = U, Mo, W). This distinct behavior is discussed as a function of the chemical nature of the different B0 hexavalent cations.

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“…6H-Type perovskites are particularly favoured when A is large (i.e. A ¼ Ba) and when one-third of the Fe is replaced by another metal cation M. [2][3][4][5][6][7] This allows, in principle, a regular ordering of Fe on the face-sharing dimer sites and the substituting metal on the corner-sharing MO 6 sites.…”

Section: Introductionmentioning

confidence: 99%

Structural Disorder and Classical Spin-Glass Behaviour in Ba3Fe2SbO9

et al. 2014

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A new 6H-type perovskite Ba 3 Fe 2 SbO 9 has been synthesised for the first time. Synchrotron and neutron powder diffraction data reveal complete structural disorder between Sb and Fe in the octahedral perovskite B sites. This results in classical spin-glass behaviour, which we characterise using magnetic susceptibility, magnetisation, and heat capacity measurements, although some evidence is seen for a transition to a partially ordered spin-glass like state below 24 K. The behaviour of Ba 3 Fe 2 SbO 9 is compared with that of the 6H-type perovskite Ba 3 Fe 2 WO 9 , which displays antiferromagnetic character below T N ¼ 290 K before entering a glassy state below T f ¼ 60 K. Differences between the magnetism in these two phases are discussed in terms of the complete structural disorder between the Fe and Sb ions in the former case, versus partial disorder (limited to the distribution and local orientation of Fe-W and Fe-Fe dimer units) in the latter.

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Etude structurale de quatre nouvelles pérovskites au cobalt

Cited by 29 publications

References 9 publications

Rational Sol–Gel-Based Synthesis Design and Magnetic, Dielectric, and Optical Properties Study of Nanocrystalline Sr₃Co₂WO₉ Triple Perovskite

Rational Sol–Gel-Based Synthesis Design and Magnetic, Dielectric, and Optical Properties Study of Nanocrystalline Sr₃Co₂WO₉ Triple Perovskite

Crystal structure and magnetism of the double perovskites Sr3Fe2TeO9 and Ba3Fe2TeO9: a neutron diffraction study

Structural Disorder and Classical Spin-Glass Behaviour in Ba3Fe2SbO9

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Etude structurale de quatre nouvelles pérovskites au cobalt

Cited by 29 publications

References 9 publications

Rational Sol–Gel-Based Synthesis Design and Magnetic, Dielectric, and Optical Properties Study of Nanocrystalline Sr3Co2WO9 Triple Perovskite

Rational Sol–Gel-Based Synthesis Design and Magnetic, Dielectric, and Optical Properties Study of Nanocrystalline Sr3Co2WO9 Triple Perovskite

Crystal structure and magnetism of the double perovskites Sr3Fe2TeO9 and Ba3Fe2TeO9: a neutron diffraction study

Structural Disorder and Classical Spin-Glass Behaviour in Ba3Fe2SbO9

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Rational Sol–Gel-Based Synthesis Design and Magnetic, Dielectric, and Optical Properties Study of Nanocrystalline Sr₃Co₂WO₉ Triple Perovskite

Rational Sol–Gel-Based Synthesis Design and Magnetic, Dielectric, and Optical Properties Study of Nanocrystalline Sr₃Co₂WO₉ Triple Perovskite