Magnetoelectrically Driven Catalytic Degradation of Organics.

Here, the catalytic degradation of organic compounds is reported by exploiting the magnetoelectric nature of cobalt ferrite-bismuth ferrite (CFO-BFO) core-shell nanoparticles. The combination of magnetostrictive CFO with multiferroic BFO gives rise to a magnetoelectric engine that purifies water under wireless magnetic fields via advanced oxidation processes, without involvement of any sacrificial molecules or cocatalysts. Magnetostrictive CoFe O nanoparticles are fabricated using hydrothermal synthesis, followed by sol-gel synthesis to create the multiferroic BiFeO shell.

A contactless positioning system for monitoring discontinuities in three dimensions with geological and geotechnical applications.

In this paper, a contactless positioning system is presented which has been designed to monitor the kinematic behavior of mechanical discontinuities in three dimensions. The positioning system comprises a neodymium magnet, fixed on one side of a discontinuity, and a magnetoresistive sensing array, fixed on the opposing side. Each of the anisotropic magnetoresistive sensors in the sensing array records the magnetic field along three orthogonal directions.

On the persistence of polar domains in ultrathin ferroelectric capacitors.

The instability of ferroelectric ordering in ultra-thin films is one of the most important fundamental issues pertaining realization of a number of electronic devices with enhanced functionality, such as ferroelectric and multiferroic tunnel junctions or ferroelectric field effect transistors. In this paper, we investigate the polarization state of archetypal ultrathin (several nanometres) ferroelectric heterostructures: epitaxial single-crystalline BaTiO films sandwiched between the most habitual perovskite electrodes, SrRuO, on top of the most used perovskite substrate, SrTiO. We use a combination of piezoresponse force microscopy, dielectric measurements and structural characterization to provide conclusive evidence for the ferroelectric nature of the relaxed polarization state in ultrathin BaTiO capacitors.

The instrumental resolution of a moire extensometer in light of its recent automatisation.

This paper assesses the instrumental resolution of a mechanical extensometer in light of its recent automatisation. The instrument takes advantage of the moire phenomenon of optical interference to measure angular rotation in two perpendicular planes and displacement in three dimensions. Our assessment systematically defines an analytical solution for the complete interpretation of a generic moire pattern and a set of mathematical approximations for the moire patterns used to measure rotation and displacement.

Calculating flux to predict future cave radon concentrations.

Cave radon concentration measurements reflect the outcome of a perpetual competition which pitches flux against ventilation and radioactive decay. The mass balance equations used to model changes in radon concentration through time routinely treat flux as a constant. This mathematical simplification is acceptable as a first order approximation despite the fact that it sidesteps an intrinsic geological problem: the majority of radon entering a cavity is exhaled as a result of advection along crustal discontinuities whose motions are inhomogeneous in both time and space.

Four-state ferroelectric spin-valve.

Spin-valves had empowered the giant magnetoresistance (GMR) devices to have memory. The insertion of thin antiferromagnetic (AFM) films allowed two stable magnetic field-induced switchable resistance states persisting in remanence. In this letter, we show that, without the deliberate introduction of such an AFM layer, this functionality is transferred to multiferroic tunnel junctions (MFTJ) allowing us to create a four-state resistive memory device.

Multisegmented FeCo/Cu nanowires: electrosynthesis, characterization, and magnetic control of biomolecule desorption.

In this paper, we report on the synthesis of FeCo/Cu multisegmented nanowires by means of pulse electrodeposition in nanoporous anodic aluminum oxide arrays supported on silicon chips. By adjustment of the electrodeposition conditions, such as the pulse scheme and the electrolyte, alternating segments of Cu and ferromagnetic FeCo alloy can be fabricated. The segments can be built with a wide range of lengths (15-150 nm) and exhibit a close-to-pure composition (Cu or FeCo alloy) as suggested by energy-dispersive X-ray mapping results.

Spintronic functionality of BiFeO3 domain walls.

Anisotropic magnetoresistance at the BiFeO3 domain walls has been observed thanks to the realization of micro-devices that allow the direct magneto-transport characterization of the domain-walls. Anisotropic magnetoresistance of ferromagnetic metals has been a pillar in spintronic technology, and now it is evidenced at the conductive domain walls of an insulating ferroelectric material, which implies that domain walls become an electrically tunable nanospintronic object.

Room-temperature negative capacitance in a ferroelectric-dielectric superlattice heterostructure.

We demonstrate room-temperature negative capacitance in a ferroelectric-dielectric superlattice heterostructure. In epitaxially grown superlattice of ferroelectric BSTO (Ba0.8Sr0.

Skin layer of BiFeO(3) single crystals.

A surface layer ("skin") different from the bulk was found in single crystals of BiFeO(3). Impedance analysis and grazing incidence x-ray diffraction reveal a phase transition at T(*)∼275±5 °C that is confined within the surface of BiFeO(3). X-ray photoelectron spectroscopy and refraction-corrected x-ray diffraction as a function of incidence angle and photon wavelength indicate a reduced electron density and an elongated out-of-plane lattice parameter within a few nanometers of the surface.