Ti diffusion in La-doped SrTiO3single crystals

Gömann, Karsten; Borchardt, G.; Gunhold, A.; Maus‐Friedrichs, W.; Baumann, H.

doi:10.1039/b315210c

Cited by 57 publications

(57 citation statements)

References 26 publications

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“…For grain growth some investigations explained changes in microstructure by the total defect concentration. 41),42) While these studies focus on oxygen vacancies, we propose strontium vacancies as dominant defect species for diffusion, densification and grain growth as proposed by Goemann et al 15), 16) We also consider the existence of an internal space charge layer at the grain boundaries 17),18),23), 43) to explain some of our findings.…”

Section: Introductionmentioning

confidence: 93%

“…Impedance data, 25) SIMS (Secondary ion mass spectrometry) measurements 10) and simulations 5) provide detailed data of the space charge properties. The typical width of the space charge region ranges from several nanometers up to 100 nm and the potential at the grain boundary is commonly determined as 0.4 1.0 V. A set of diffusion data for Ti and Sr in SrTiO 3 single crystals is presented by Goemann et al, 15), 16) which indicates that both species diffuse via strontium vacancies at high temperature. Data for strontium vacancy mobilities are presented by Poignant and Juda 26) for polycrystalline (Sr,Ca)(Ti,Nb)O 3 and Meyer et al 27) for single crystalline SrTiO 3 .…”

Section: Introductionmentioning

confidence: 99%

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Sintering and grain growth in SrTiO3: impact of defects on kinetics

Lemke

Rheinheimer

Hoffmann

2016

J. Ceram. Soc. Japan

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The microstructural evolution of undoped and iron doped SrTiO 3 is analyzed during sintering at 1280°C in air and reducing atmosphere. The focus is on densification and grain growth during different holding times investigated by dilatometric studies and microstructural analysis. The sintering equations developed by Coble are used to characterize sintering. The influence of point defects on diffusion, densification and grain growth is evaluated using basic defect chemistry equations. A space charge concept at the grain boundaries is added to bulk defect chemistry concepts to understand sintering of perovskites, since the major part of mass transport during sintering occurs in this region. The extension of the defect chemistry concept allows to explain the change in diffusion mechanism during sintering (grain boundary diffusion or bulk diffusion) as well as grain growth stagnation observed in iron doped SrTiO 3 . The results are used to separate the complex interplay of densification and grain growth. While grain growth decreases with increasing defect concentration, no clear trend is observed for the densification kinetics, since both grain growth and diffusion are relevant. The results show that grain growth during sintering provides comparable results to grain growth experiments in dense SrTiO 3 and, thus, pore drag seems not to be important. The calculated diffusion coefficients are in good agreement with literature data and show a strong dependency on the concentration of strontium vacancies.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Sintering and grain growth in SrTiO3: impact of defects on kinetics

Lemke

Rheinheimer

Hoffmann

2016

J. Ceram. Soc. Japan

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“…Gomann et al [13] reported also that diffusion of Sr and Ti cation takes place generally through strontium vacancies. The influence of defect chemistry on ionic conductivity of SrTiO 3 was studied by Zhao et al [6].…”

Section: Introductionmentioning

confidence: 99%

Microstructural and electrical properties of Y0.07Sr0.93-x TiO3-δ perovskite ceramics

et al. 2012

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Abstract:In order to find a relationship between electrical and microstructural properties, yttrium-doped strontium titanate (7 mol%) with various values of strontium nonstoichiometry was investigated and shown in this work. It has been observed that yttrium doping can affect the electrical properties of SrTiO 3 to a great extent. Moreover, the microstructural and electrical properties can be influenced by strontium nonstoichiometry. The defect chemistry explaining obtained results was also suggested and discussed. PACS

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“…As this figure shows, the activation energy for the spontaneous formation of the superlattice is 0.25 eV, which is much smaller than that reported for Ti diffusion in SrTiO 3 (3.3 eV). 30 Reportedly, the application of a magnetic field during PLD enhances excitation and ionization in the plume. [31][32][33][34][35][36][37] Actually, as shown in Figure 4d, weak emission peaks from neutral atoms (Sr and Ti) were observed in the plume when no magnetic field was applied.…”

Section: Resultsmentioning

confidence: 99%

Magnetic-field-induced spontaneous superlattice formation via spinodal decomposition in epitaxial strontium titanate thin films

et al. 2016

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Periodically structured nanomaterials such as superlattices have a wide range of applications. Many electronic devices have been fabricated from these materials. The formation of spontaneous layer structures using epitaxial growth has also been reported for many compound semiconductors but for very few ceramics. We demonstrate that strontium titanate (Sr-Ti-O) thin films having an A-site excess composition in the perovskite structure deposited by pulsed laser deposition under a magnetic field show a spontaneously formed superlattice structure. The spontaneous superlattice formation mechanism has been proven to exhibit spinodal decomposition. Preparation of a part of the phase diagram for Sr-Ti-O thin films is reported for the first time. Although SrTiO 3 bulk is quantum paraelectric, previous reports have described that strained SrTiO 3 thin films show room-temperature ferroelectricity, especially along the in-plane direction. However, induced ferroelectricity along the out-of-plane direction has been reported in films with a limited thickness of less than 10 ml. The results show that the Sr-Ti-O thin films with spontaneously formed superlattice structures exhibit room-temperature ferroelectricity even when 300 nm thick. The induced ferroelectricity is brought about by the strain along the out-of-plane direction and is explained based on thermodynamic considerations.

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Ti diffusion in La-doped SrTiO₃single crystals

Cited by 57 publications

References 26 publications

Sintering and grain growth in SrTiO<sub>3</sub>: impact of defects on kinetics

Sintering and grain growth in SrTiO<sub>3</sub>: impact of defects on kinetics

Microstructural and electrical properties of Y0.07Sr0.93-x TiO3-δ perovskite ceramics

Magnetic-field-induced spontaneous superlattice formation via spinodal decomposition in epitaxial strontium titanate thin films

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