Electrical properties of the Sr2Ru1−xTixO4 solid solutions

Miwa, Kenji; Kagomiya, Isao; Ohsato, Hitoshi; Sakai, Hiroshi; Maeda, Yukinori

doi:10.1016/j.jeurceramsoc.2007.02.146

Cited by 13 publications

(4 citation statements)

References 12 publications

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“…The unit-cell and positional parameters obtained from neutron diffraction data measured by the Echidna diffractometer at 298 K agree with those from synchrotron X-ray diffraction data at 300 K, from TOF SuperHRPD and iMATERIA neutron data at RT, and from DFT calculations. The present refined crystal parameters of LaSrAlO 4 and Sr 2 TiO 4 are consistent with those presented in the literature. , For LaSrAlO 4 ( A = La,Sr and B = Al), the B –(apical oxygen atom O2) distance, d ( B –O2) (2.0535(16) Å) is longer than that of B –(equatorial oxygen atom O1) (1.87832(3) Å) ( B = Al): [ d ( B –O2)/ d ( B –O1) = 1.0932(9) > 1]. For Sr 2 TiO 4 ( A = Sr and B = Ti), the B –O2 distance (1.981(3) Å) is nearly equal to that of B –O1 (1.94328(4) Å): [ d ( B –O2)/ d ( B –O1) = 1.0194(15)].…”

Section: Resultssupporting

confidence: 89%

Structural Origin of the Anisotropic and Isotropic Thermal Expansion of K₂NiF₄-Type LaSrAlO₄ and Sr₂TiO₄

Kawamura¹,

Yashima²,

Fujii³

et al. 2015

Inorg. Chem.

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K2NiF4-type LaSrAlO4 and Sr2TiO4 exhibit anisotropic and isotropic thermal expansion, respectively; however, their structural origin is unknown. To address this unresolved issue, the crystal structure and thermal expansion of LaSrAlO4 and Sr2TiO4 have been investigated through high-temperature neutron and synchrotron X-ray powder diffraction experiments and ab initio electronic calculations. The thermal expansion coefficient (TEC) along the c-axis (αc) being higher than that along the a-axis (αa) of LaSrAlO4 [αc = 1.882(4)αa] is mainly ascribed to the TEC of the interatomic distance between Al and apical oxygen O2 α(Al-O2) being higher than that between Al and equatorial oxygen O1 α(Al-O1) [α(Al-O2) = 2.41(18)α(Al-O1)]. The higher α(Al-O2) is attributed to the Al-O2 bond being longer and weaker than the Al-O1 bond. Thus, the minimum electron density and bond valence of the Al-O2 bond are lower than those of the Al-O1 bond. For Sr2TiO4, the Ti-O2 interatomic distance, d(Ti-O2), is equal to that of Ti-O1, d(Ti-O1) [d(Ti-O2) = 1.0194(15)d(Ti-O1)], relative to LaSrAlO4 [d(Al-O2) = 1.0932(9)d(Al-O1)]. Therefore, the bond valence and minimum electron density of the Ti-O2 bond are nearly equal to those of the Ti-O1 bond, leading to isotropic thermal expansion of Sr2TiO4 than LaSrAlO4. These results indicate that the anisotropic thermal expansion of K2NiF4-type oxides, A2BO4, is strongly influenced by the anisotropy of B-O chemical bonds. The present study suggests that due to the higher ratio of interatomic distance d(B-O2)/d(B-O1) of A2(2.5+)B(3+)O4 compared with A2(2+)B(4+)O4, A2(2.5+)B(3+)O4 compounds have higher α(B-O2), and A2(2+)B(4+)O4 materials exhibit smaller α(B-O2), leading to the anisotropic thermal expansion of A2(2.5+)B(3+)O4 and isotropic thermal expansion of A2(2+)B(4+)O4. The "true" thermal expansion without the chemical expansion of A2BO4 is higher than that of ABO3 with a similar composition.

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Section: Resultssupporting

confidence: 89%

Structural Origin of the Anisotropic and Isotropic Thermal Expansion of K₂NiF₄-Type LaSrAlO₄ and Sr₂TiO₄

Kawamura¹,

Yashima²,

Fujii³

et al. 2015

Inorg. Chem.

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“…Powder X-ray diffraction patterns of the Sr 2 TiO 4 reaction intermediates and products after the initial aerobic heating at 1100 °C for 6 h (black) and after an additional 21 h (red). The reference diffraction patterns of SrO (S), TiO 2 -R (R), SrTiO 3 (∞), Sr 2 TiO 4 (1), and Sr 3 Ti 2 O 7 (2) are from the literature. ,,,, …”

Section: Resultsmentioning

confidence: 99%

“…The reference diffraction patterns of SrO (S), TiO 2 -R (R), SrTiO 3 (∞), Sr 2 TiO 4 (1), and Sr 3 Ti 2 O 7 (2) are from the literature 15,32,36,37…”

mentioning

confidence: 99%

Spectroscopic Study of the Reversible Chemical Reduction and Reoxidation of Substitutional Cr Ions in Sr₂TiO₄

et al. 2017

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The solid-state synthesis and controllable speciation of Cr dopants in the layered perovskite SrTiO is reported. We employed a chemical reduction procedure with NaBH at relatively mild temperatures (<450 °C) to impart sensitive control over the relative concentration of Cr dopants, the charge-state of oxygen-vacancy defects, and presence of Ti defects in highly reduced Cr-doped SrTiO. The electron paramagnetic resonance (EPR) spectra of the reduced powder samples reveal a 12-fold increase in the Cr concentration within the axially compressed Ti-site of the SrTiO host. The increase in Cr content is achieved through the reduction of higher-valence Cr ions that are either EPR silent or diamagnetic. The spin-Hamiltonian parameters for Cr substituted at the B-site of SrTiO were refined to D = -201 × 10 cm, g = 1.980, and g = 1.978. In addition, the Cr ion exhibits a temperature-dependent axial component to the zero-field splitting of the A ground term that is accounted for by ligand field theory and an isotropic contraction of the SrTiO lattice with decreasing temperature. The observed changes to the electronic structure upon reduction are quantitatively reversible upon reoxidation of the sample under aerobic annealing at the same temperature and duration as the reduction conditions. This temperature dependence of the Cr content in the Cr-doped SrTiO powders is discussed and contrasted to our recent study on Cr-doped SrTiO.

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“…All RP phases in table 2, including the prototypical perovskite when treated as n = 0, demonstrate a direct proportionality between complexity and amount of layers: I G ∝ n (R 2 = 0.998). In contrast to the ABX 3 compounds with fluorides, which typically adapt the perovskite structure, (Natarajan et al, 1978), c (Miwa et al, 2007), d (Kruglik et al, 1989), e (Lukaszewicz, 1959), f (Villars & Cenzual, 2012a), g (Villars & Cenzual, 2012b), h , i , j (Teske & Müller-Buschbaum, 1971), k (Teske & Müller-Buschbaum, 1969), l (Gutau & Müller-Buschbaum, 1990).…”

Section: Ruddlesden-popper Seriesmentioning

confidence: 99%

crystIT: Complexity and Configurational Entropy of Crystal Structures via Information Theory

Kaußler¹,

Kieslich

2020

Preprint

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<div>The information content of a crystal structure as conceived by information theory has recently proved as an intriguing approach to calculate the complexity of a crystal structure within a consistent concept. Given the relatively young nature of the field, theory development is still at the core of on-going research efforts. In this work we provide an update to the current theory, improving the formulas that evaluation of crystal structures with partial occupancies as frequently found in disordered system is feasible. To encourage wider application and further theory development we incorporate the updated formulas in crystIT (crystal structure & Information Theory), an open-source python-based program that allows for calculating various complexity measures of crystal structures based on a standardized *.cif file.</div>

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Electrical properties of the Sr2Ru1−xTixO4 solid solutions

Cited by 13 publications

References 12 publications

Structural Origin of the Anisotropic and Isotropic Thermal Expansion of K₂NiF₄-Type LaSrAlO₄ and Sr₂TiO₄

Structural Origin of the Anisotropic and Isotropic Thermal Expansion of K₂NiF₄-Type LaSrAlO₄ and Sr₂TiO₄

Spectroscopic Study of the Reversible Chemical Reduction and Reoxidation of Substitutional Cr Ions in Sr₂TiO₄

crystIT: Complexity and Configurational Entropy of Crystal Structures via Information Theory

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Electrical properties of the Sr2Ru1−xTixO4 solid solutions

Cited by 13 publications

References 12 publications

Structural Origin of the Anisotropic and Isotropic Thermal Expansion of K2NiF4-Type LaSrAlO4 and Sr2TiO4

Structural Origin of the Anisotropic and Isotropic Thermal Expansion of K2NiF4-Type LaSrAlO4 and Sr2TiO4

Spectroscopic Study of the Reversible Chemical Reduction and Reoxidation of Substitutional Cr Ions in Sr2TiO4

crystIT: Complexity and Configurational Entropy of Crystal Structures via Information Theory

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Product

Resources

About

Structural Origin of the Anisotropic and Isotropic Thermal Expansion of K₂NiF₄-Type LaSrAlO₄ and Sr₂TiO₄

Structural Origin of the Anisotropic and Isotropic Thermal Expansion of K₂NiF₄-Type LaSrAlO₄ and Sr₂TiO₄

Spectroscopic Study of the Reversible Chemical Reduction and Reoxidation of Substitutional Cr Ions in Sr₂TiO₄