Оксидні матеріали електронної техніки – отримання, властивості, застосування.

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Start date: 2012Subject: search.filters.subject.crystal structure

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    Concentration and temperature-driven phase transitions in the NdAlO3-EuAlO3 system
    (Видавництво Львівської політехніки, 2012) Ohon, N.; Pashuk, A.; Hoffmann, S.; Vasylechko, L.
    Phase and structural behaviour in the NdAlO3– EuAlO3 system has been studied in a whole concentration range. Depending on x two kinds of solid solutions Nd1-xEuxAlO3 one with rhombohedral (x £ 0.15) and one with orthorhombic (x ³ 0.25) symmetry exist at room temperature. A morphotropic phase transition occurs at x ≈ 0.20, where the co-existence of both phases was observed. First-order structural phase transition Pbnm↔R 3 c has been detected in Nd0.6Eu0.4AlO3 at 627 K both from in situ high-temperature X-ray synchrotron powder diffraction and thermal analysis data.
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    Phase composition and crystal structure of the RE-substituted BiFeO3 (RE = Er, Tm, Yb)
    (Видавництво Львівської політехніки, 2012) Kuz, O.; Handysh, V.; Prots, Yu.; Vasylechko, L.
    The work deals with the study of the phase and structural behaviour of the rare-earth substituted BiFeO3. Xray powder diffraction examinations revealed that the polar R3c phase in the Bi1-xRExFeO3 systems with RE = Er, Tm and Yb do not exceed 7, 4 and 3 mol.% of rare earth, respectively. Partial substitution of Er and Tm for the Bi sites in BiFeO3 reduce the temperature of the ferroelectric phase transition R3c-Pbnm on 30-60 K.
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    Concentration and temperature-driven phase transitions in the NdAlO3-EuAlO3 system
    (Видавництво Львівської політехніки, 2012) Ohon, N.; Pashuk, A.; Hoffmann, S.; Vasylechko, L.
    Phase and structural behaviour in the NdAlO3– EuAlO3 system has been studied in a whole concentration range. Depending on x two kinds of solid solutions Nd1-xEuxAlO3 one with rhombohedral (x £ 0.15) and one with orthorhombic (x ³ 0.25) symmetry exist at room temperature. A morphotropic phase transition occurs at x ≈ 0.20, where the co-existence of both phases was observed. First-order structural phase transition Pbnm↔R 3 c has been detected in Nd0.6Eu0.4AlO3 at 627 K both from in situ high-temperature X-ray synchrotron powder diffraction and thermal analysis data.
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    Crystal and twin structure of LSGMn-05 anode material for SOFC
    (Видавництво Львівської політехніки, 2012) Tataryn, T.; Vasylechko, L.; Savytskii, D.; Berkowski, M.; Paulmann, C.; Bismayer, U.
    The structure of perovskite-type La0.95Sr0.05Ga0.95Mn0.05O3-x crystals has been investigated using high-resolution X-ray powder diffraction technique in the temperature range of 298–1173 К. A phase transition from orthorhombic (Pbnm) to rhombohedral (R 3 c) has been detected near 340 К. A chevron-like configuration of ferroelastic domain structure was observed in rhombohedral La0.95Sr0.05Ga0.95Mn0.05O3-x crystal using the Laue technique. The chevron-like pattern is formed by the intersection of Wtype domain walls (211), (101) and (110).
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    The size factor as criterion for the formation of M14Cu24O41 phases
    (Видавництво Львівської політехніки, 2012) Zaremba, О.; Gladyshevskii, R.
    The size factor was analyzed as criterion for the formation of M14Cu24O41 phases. The minimum critical value of average radius of the cations in position M at which an M14Cu24O41 phase is formed was found to be equal to 1.21 Å and the maximum critical value to 1.40 Å.
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    Influence of cation substitution on spin-state transitions in mixed RE cobaltites and chromites
    (Видавництво Львівської політехніки, 2012) Vasylechko, L.; Bell, A. M. T.
    Phase and structural behaviour of new mixed cobaltites R1-xR’xCoO3 (R, R’ = La, Pr, Nd, Sm, Eu, Gd) and cobaltites-chromites RCo0.5Cr0.5O3 (R = Pr, Sm, Eu, Gd) has been studied in the temperature range of 298–1173K. Strong anomalies in the lattice expansion reflecting the changes in spin state of Co3+ ions, are found. Correlations between the structural parameters, characteristic temperatures of thermal expansion coefficients and the temperatures of spinstate transitions in the mixed RE cobaltites has been established.
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    Growth and characterization of pure and Yb-Doped Ca9Y(VO4)7 single crystals
    (Видавництво Львівської політехніки, 2012) Kosmyna, M. B.; Mateychenko, P. V.; Nazarenko, B. P.; Puzikov, V. M.; Shekhovtsov, A. N.; Paszkowicz, W.; Ermakova, O.; Romanowski, P.; Yasukevich, A. S.; Kuleshov, N. V.; Kisel, V. E.; Gulevich, A. E.; Demesh, M. P.
    Pure and Yb-doped Ca9Y(VO4)7 (CYVO) single crystals were grown using the Czochralski method. Their crystal structure was determined using powder diffraction and the defect structure was characterized using highresolution diffraction. The undoped crystal is found to be composed of a transparent and an opaque parts. In the latter, yttrium-rich inclusions were detected. Spectral-kinetic characteristics of Yb3 -doped crystals is reported.