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A reliable and flexible synthesis route was used for processing high density Ni-BaTiO3 nanocable arrays based on wet chemical impregnation and subsequent electrodeposition within a highly ordered unidirectional porous alumina membrane. The core-shell structure was carefully investigated by bright field scanning transmission electronic microscopy coupled with energy dispersive X-ray spectroscopy. The strength of the dipolar interaction arising from the packing density of the magnetic nanowires was correlated with the BaTiO3 wall thickness through magnetometry and ferromagnetic resonance measurements. Our approach opens a pathway to obtain optimized nanostructured multiferroic composites exhibiting tunable magnetic properties. [ABSTRACT FROM AUTHOR]

Sealed-tube synthesis of BiMn2O5 materials and their physical properties have rationally been reinvestigated depending on the reactants. The aim of the study was to characterize its potential multiferroic properties and to investigate the anomalous magnetic properties in relation to the expected ferroelectric properties. Rietveld refinement of the room temperature X-ray diffraction data shows the stability of the crystallographic structure with a Mn3+/Mn4+ ratio far from 1 because of bismuth and oxygen deficiencies despite the sealed-tube synthesis. Our detailed magnetic susceptibility and specific heat data analysis unambiguously support an intrinsic anomalous magnetic behavior in relation to the establishment of a magnetic short-range ordering far from the Néel temperature. Around room temperature, oxygen vacancies are responsible for supporting the dielectric loss peak measured, and, interestingly, the so-called T*, which was underlined in relation to an anomalous phonon shift (García-Flores, A. F.; et al. Phys. Rev. B2006, 73, 104411), is not a characteristic temperature in relation to the multiferroic properties because no ferroelectric transition was detected. [ABSTRACT FROM AUTHOR]

A new strategy to elaborate (1-3) type multiferroic nanocomposites with controlled dimensions and vertical alignment is presented. The process involves a supported nanoporous alumina layer as a template for growth of free-standing and vertically aligned CoFe 2 nanopillars using a room temperature pulsed electrodeposition process. Ba 0.70 Sr 0.30 TiO 3 -CoFe 2 O 4 multiferroic nanocomposites were grown through direct deposition of Ba 0.7 Sr 0.3 TiO 3 films by radio-frequency sputtering on the top surface of the pillar structure, with in situ simultaneous oxidation of CoFe 2 nanopillars. The vertically aligned multiferroic nanocomposites were characterized using various techniques for their structural and physical properties. The large interfacial area between the ferrimagnetic and ferroelectric phases leads to a magnetoelectric voltage coefficient as large as ∼320 mV cm -1 Oe -1 at room temperature, reaching the highest values reported so far for vertically architectured nanocomposite systems. This simple method has great potential for large-scale synthesis of many other hybrid vertically aligned multiferroic heterostructures.