Rare earth titanates with a perovskite structure

Brous, J.; Fankuchen, I.; Banks, E.

doi:10.1107/s0365110x53000156

Cited by 182 publications

(90 citation statements)

References 3 publications

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“…In the system of RTiO 3 (R: rare earth elements), only europium titanate has a cubic structure like that of alkaline earth titanate. 13,14) The titanium ion is tetravalent in europium titanate, and is not trivalent as in other rare earth titanates. The structure and some magnetic and electrical properties of europium titanates have been investigated; 15,16) however, study of thermoelectric properties has not been conducted yet.…”

Section: Introductionmentioning

confidence: 99%

“…The structure and some magnetic and electrical properties of europium titanates have been investigated; 15,16) however, study of thermoelectric properties has not been conducted yet. Europium titanate has a lattice parameter similar to that of strontium titanate, 13,14) but the atomic mass of europium is larger than that of barium. The comparison of the thermoelectric properties to those of alkaline earth titanate can be important for the investigation of oxide thermoelectric materials.…”

Section: Introductionmentioning

confidence: 99%

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Thermoelectric Properties of Lanthanum-Doped Europium Titanate

et al. 2005

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The thermoelectric properties of lanthanum-doped polycrystalline perovskite-type europium titanate were measured from room temperature to 900 K and compared to those of MTiO 3 (M ¼ Ca, Sr, Ba). The differences in the titanates were calculated in terms of the differences of A-site ion and Ti-O distance that determined the covalent bonding strength. The A-site ion appeared to have little influence on the electrical properties. The small Ti-O(Ti) distance results in strong bonding and it causes high thermal conductivity together with high electrical conductivity. Europium titanate showed power factor similar to and thermal conductivity lower than those of the strontium titanate. Eu 0:9 La 0:1 TiO 3 showed the highest dimensionless figure of merit of 0.25 at 900 K.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties of Lanthanum-Doped Europium Titanate

et al. 2005

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“…8,9 In this paper, we present the case of magnetoelectric EuTiO 3 showing an unusual interplay between dielectric, magnetic, and structural degrees of freedom. At room temperature, its crystal structure has been reported to be Pm-3m and no phase changes have been observed to occur down to 108 K, 10 as deduced from lab source powder x-ray diffraction. From the dielectric point of view, EuTiO 3 is described as a quantum paraelectric, as its low-temperature dielectric constant increases on cooling and saturates below approximately 30 K. 11 No long-range polarization is known to set in, despite high values of susceptibility, typical of a paraelectric state stabilized by quantum fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Role of intrinsic disorder in the structural phase transition of magnetoelectric EuTiO3

et al. 2012

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Up to now, the crystallographic structure of the magnetoelectric perovskite EuTiO 3 has been considered to remain cubic down to low temperature. Here we present high-resolution synchrotron x-ray powder-diffraction data showing the existence of a structural phase transition, from cubic P m-3m to tetragonal I 4/mcm, involving TiO 6 octahedra tilting, in analogy to the case of SrTiO 3 . The temperature evolution of the tilting angle and of the full width at half maximum of the (200) cubic reflection family indicate a critical temperature T c = 235 K. This critical temperature is well below the recent anomaly reported by specific-heat measurement at T A ∼ 282 K. By performing atomic pair distribution function analysis on diffraction data, we provide evidence of a mismatch between the local (short-range) and the average crystallographic structures in this material. Below the estimated T c , the average model symmetry is fully compatible with the local environment distortion, but the former is characterized by a reduced value of the tilting angle compared to the latter. At T = 240 K, data show the presence of local octahedra tilting identical to the low-temperature one, while the average crystallographic structure remains cubic. On this basis, we propose that intrinsic lattice disorder is of fundamental importance in the understanding of EuTiO 3 properties.

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“…10,11 At room temperature bulk EuTiO 3 possesses a cubic crystal structure described by the prototype perovskite P m3m space group. 12 A structural transition 13,14 to the tetragonal I 4/mcm space group has been recently reported. The transition temperature is still controversial.…”

Section: Introductionmentioning

confidence: 99%

EuTiO3magnetic structure studied by neutron powder diffraction and resonant x-ray scattering

et al. 2012

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We combine neutron powder diffraction and x-ray single-crystal magnetic diffraction at the Eu L 2 edge to scrutinize the magnetic motif of the Eu ions in magnetoelectric EuTiO 3 . Our measurements are consistent with an antiferromagnetic G-type pattern with the Eu magnetic moments ordering along the a,b -plane diagonal. Recent reports of a novel transition at 2.75 K with a flop of magnetic moments upon poling the sample in an electric field cannot be confirmed for a nonpoled sample. Our neutron diffraction data do not show any significant change of the structure below the Néel temperature. Magnetoelastic coupling, if present, is therefore expected to be negligible.

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Rare earth titanates with a perovskite structure

Cited by 182 publications

References 3 publications

Thermoelectric Properties of Lanthanum-Doped Europium Titanate

Thermoelectric Properties of Lanthanum-Doped Europium Titanate

Role of intrinsic disorder in the structural phase transition of magnetoelectric EuTiO3

EuTiO3magnetic structure studied by neutron powder diffraction and resonant x-ray scattering

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