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A highly oriented PbTiO3 thin film deposited on a MgO single crystal was investigated by Raman spectroscopy as a function of the temperature and compared with a PbTiO3 single crystal. A shift in the transition temperature of the film was deduced from the difference in the temperature variations of the soft mode frequency between the single crystal and the film. Also, the linewidth and integrated intensity of this soft mode functioned differently from past studies.

Polarized Raman spectra of heteroepitaxial (Ba0.7Sr0.3)TiO3 thin film deposited on the (001)MgO substrate is studied in the broad temperature range from 30 to 1300 K. The results of the study shows that the ferroelectric-paraelectric phase transition is markedly shifted to higher temperatures with respect to the bulk ceramics of the same composition.

Provides information on a study investigating a Raman study of a highly oriented PbTiO3 thin film deposited on a MgO single crystal as a function of the temperature. Methodology used to conduct the study; Information on the thin film preparation and characterization; Temperature evolution of the Raman spectra; Findings of the study.

Solid solution crystals of ternary 1:1 (PbSc½Ta½O3-PbSc½Nb½O3) and 1:2 (PbMg⅓Nb2/3O3-PbSc½Nb½O3) perovskites were grown from the flux. X-ray supercell reflections due to B-cation ordering were observed for as-grown crystals. The same regularities of cation ordering during the crystal growth were found to be valid for both systems: the disordered structure is formed first even when the crystallization temperature is much lower than the temperature Tt of the compositional order-disorder phase transition and the disordered state is non-equilibrium. The ordering then starts via a diffusion-type mechanism, its rate depending greatly on the relation of crystallization temperature and Tt. [ABSTRACT FROM AUTHOR]

The relaxation dynamics of charge carriers in an epitaxial La[sub 0.7]Ca[sub 0.3]MnO[sub 3] film was studied by the light reflection method with a femtosecond time resolution in a wide temperature range. The relaxation of time-resolved photoinduced reflections was shown to be two-component in the whole temperature range including the paramagnetic dielectric–ferromagnetic metal transition at T ≈ 150–160 K. The fast relaxation component had a maximum lifetime (τ ∼ 500 ps) in the transition region, and its contribution to relaxation increased as temperature decreased. The lifetime of the slow component was minimum (τ ∼ 15 fs) in the transition region. In addition, fast oscillations assigned to coherent phonons appeared in photoinduced responses at T < 200 K. The dephasing time of these oscillations increased as temperature decreased, whereas their frequency changed insignificantly. © 2003 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

(1 - x )PbMg 1/3 Nb 2/3 O 3 -( x )PbSc 1/2 Nb 1/2 O 3 solid solution crystals have been grown by the flux method. X-ray supercell reflections due to B-cation ordering were observed for crystals in the 0.1 < x < 0.65 compositional range. In as-grown crystals diffuseness of dielectric permittivity maximum is the lowest for x = 0.65 composition and increases toward the end members of solid solution. Such behavior is assumed to be due to the random-site ordering of B-site cations and non-monotonic dependence of the compositional order-disorder phase transition temperature on concentration. [ABSTRACT FROM AUTHOR]