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تسجيل مستخدم جديدUltrathin BaTiO3 templates for multiferroic nanostructures
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Structural, electronic and dielectric properties of high-quality ultrathin BaTiO3 films are investigated. The films, which are grown by ozone-assisted molecular beam epitaxy on Nb-doped SrTiO3 (001) substrates and having thicknesses as thin 8 unit cells (3.2 nm), are unreconstructed and atomically smooth with large crystalline terraces. A strain-driven transition to 3D island formation is observed for films of of 13 unit cells thickness (5.2 nm). The high structural quality of the surfaces, together with the dielectric properties similar to bulk BaTiO3 and dominantly TiO2 surface termination, make these films suitable templates for the synthesis of high-quality metal-oxide multiferroic heterostructures for the fundamental study and exploitation of magneto-electric effects, such as a recently proposed interface effect in Fe/BaTiO3 heterostructures based on Fe-Ti interface bonds.
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annot be explained by extrinsic effects, such as interfacial passive layers or strain relaxation, nor by homogeneous domain models. Based on domain nuclei formation model, the observed EC behavior is explainable via a quantitative level. A crossover of domain shape from a half-prolate spheroid to a cylinder is also suggested at d~ 15 nm, exhibiting good agreement with experimental results.
Analytical expressions for the magnetoelastic anisotropy constants of cubic magnetic systems are derived for rectangular and oblique distortions originating from epitaxial growth on substrates with lower crystal symmetry. In particular, the temperatu
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