Observation Of Structural Transition Research Articles

Phase Transitions in Liquid Crystal Doped with Magnetic Particles of Different Shapes

In this study, observations of structural transitions in ferronematics based on the thermotropic nematic 4-trans-4′-n-hexyl-cyclohexyl-isothiocyanato-benzene (6CHBT) are described. Droplets of the nematic phase in the isotropic phase were observed in solutions of nematogenic 6CHBT dissolved in phenyl isocyanate and 6CHBT dissolved in phenyl isocyanate and doped with magnetic particles of different shapes (nanorods and chain-like particles). Magneto-dielectric measurements of structural transitions in these new systems enable to estimate of the type of anchoring of the nematic molecules on the magnetic particles surface.

Observation of structural transitions and Jahn–Teller distortion in LaMnO3-doped BiFeO3 thin films

Structural and functional properties of multiferroic BiFeO3 are currently under debate. We utilized Raman spectroscopy to characterize the structural properties of pure and up to 10mol% LaMnO3-doped polycrystalline BiFeO3 thin films. All films were identified as phase-pure perovskite using x-ray diffraction (XRD). Although XRD has insufficient sensitivity for detailed thin film analysis, Raman experiments showed that pure BiFeO3 structure is best described as monoclinic, and that doping with LaMnO3 causes substantial modifications, namely, Jahn–Teller distortions to the (Mn,Fe)3+O6 octahedra accompanied by structural transition toward orthorhombic. Manganese substitution is shown to be the main cause of these changes.