Ferroelectric resistive switching behavior in two-dimensional materials/BiFeO hetero-junctions.

Integrating two-dimensional (2D) materials with ferroelectric thin films may result in unique characteristics and novel applications due to the coupling between their intrinsic characters. Here, we observed the ferroelectric resistive switching behavior in both graphene/BFO and MoS2/BFO heterojunctions, which stems from the modulation of contact barriers and depletion width at the hetero-interface induced by the ferroelectric polarization. Besides, the ferroelectric resistive switching behavior in both graphene/BFO and MoS2/BFO depends on the thicknesses of the corresponding 2D materials, because the thickness-dependent work function or conductivity of 2D materials could change the contact barrier heights and widths at the interface of 2D materials and ferroelectrics.

Magnetic and Photoluminescent Coupling in SrTiFeO/ZnO Vertical Nanocomposite Films.

Self-assembled growth of SrTiFeO (STF)/ZnO vertical nanocomposite films by combinatorial pulsed laser deposition is described. The nanocomposite films form vertically aligned columnar epitaxial nanostructures on SrTiO substrates, in which the STF shows room-temperature magnetism. The magnetic properties are discussed in terms of strain states, oxygen vacancies, and microstructures.

Magnetic Phase Formation in Self-Assembled Epitaxial BiFeO3-MgO and BiFeO3-MgAl2O4 Nanocomposite Films Grown by Combinatorial Pulsed Laser Deposition.

Self-assembled epitaxial BiFeO3-MgO and BiFeO3-MgAl2O4 nanocomposite thin films were grown on SrTiO3 substrates by pulsed laser deposition. A two-phase columnar structure was observed for BiFeO3-MgO codeposition within a small window of growth parameters, in which the pillars consisted of a magnetic spinel phase (Mg,Fe)3O4 within a BiFeO3 matrix, similar to the growth of BiFeO3-MgFe2O4 nanocomposites reported elsewhere. Further, growth of a nanocomposite with BiFeO3-(CoFe2O4/MgO/MgFe2O4), in which the minority phase was grown from three different targets, gave spinel pillars with a uniform (Mg,Fe,Co)3O4 composition due to interdiffusion during growth, with a bifurcated shape from the merger of neighboring pillars.

SrGa(0.7)Co(0.3)O(3-δ) perovskite-cobalt oxide-metal nanocomposite films: magnetic and optical properties.

Two-phase nanocomposite films consisting of metallic Co nanoparticles below 50 nm diameter in a perovskite matrix were grown by pulsed laser deposition onto (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) and silicon substrates from a target of SrGa0.

Multiferroic behavior of templated BiFeO3-CoFe2O4 self-assembled nanocomposites.

Self-assembled BiFeO3-CoFe2O4 nanocomposites were templated into ordered structures in which the ferrimagnetic CoFe2O4 pillars form square arrays of periods 60-100 nm in a ferroelectric BiFeO3 matrix. The ferroelectricity, magnetism, conductivity, and magnetoelectric coupling of the ordered nanocomposites were characterized by scanning probe microscopy. The insulating BiFeO3 matrix exhibited ferroelectric domains, whereas the resistive CoFe2O4 pillars exhibited single-domain magnetic contrast with high anisotropy due to the magnetoelasticity of the spinel phase.

Combinatorial pulsed laser deposition of magnetic and magneto-optical Sr(GaxTiyFe0.34-0.40)O3-δ perovskite films.

Ferromagnetic Sr(GaxTiyFe0.34-0.40)O3-δ (0.

Hierarchical templating of a BiFeO3-CoFe2O4 multiferroic nanocomposite by a triblock terpolymer film.

A process route to fabricate templated BiFeO3/CoFe2O4 (BFO/CFO) vertical nanocomposites is presented in which the self-assembly of the BFO/CFO is guided using a self-assembled triblock terpolymer. A linear triblock terpolymer was selected instead of a diblock copolymer in order to produce a square-symmetry template, which had a period of 44 nm. The triblock terpolymer pattern was transferred to a (001) Nb:SrTiO3 substrate to produce pits that formed preferential sites for the nucleation of CFO crystals, in contrast to the BFO, which wetted the flat regions of the substrate.

Templated self-assembly of functional oxide nanocomposites.

In perovskite/spinel self-assembled oxide nanocomposites, the substrate surface plays a dominant role in determining the final morphology. Topgraphic features, such as pits and trenches, are written in the substrate using either Focused Ion Beam or wet etching through a block co-polymer mask. These features are effective at templating the self-assembly, resulting in a wide range of attainable nano-assemblies.

Thin film knitting pattern morphology from a miktoarm star terpolymer.

Thin film knitting pattern from a miktoarm star terpolymer is demonstrated. Such structures have been predicted but not observed in bulk or thin film form. The knitting pattern exhibits well organized periodic structures consisting of undulating lamellae and alternating cylinders, with well-defined defects that result in sharp 90° bends and T junctions.