Jean-Luc Maurice

Mapping the spatial distribution of charge carriers in LaAlO3/SrTiO3 heterostructures

At the interface between complex insulating oxides, novel phases with interesting properties may occur, such as the metallic state reported in the LaAlO(3)/SrTiO(3) system . Although this state has been predicted and reported to be confined at the interface, some studies indicate a much broader spatial extension, thereby questioning its origin. Here, we provide for the first time a direct determination of the carrier density profile of this system through resistance profile mappings collected in cross-section LaAlO(3)/SrTiO(3) samples with a conducting-tip atomic force microscope (CT-AFM). We find that, depending on specific growth protocols, the spatial extension of the high-mobility electron gas can be varied from hundreds of micrometres into SrTiO(3) to a few nanometres next to the LaAlO(3)/SrTiO(3) interface. Our results emphasize the potential of CT-AFM as a novel tool to characterize complex oxide interfaces and provide us with a definitive and conclusive way to reconcile the body of experimental data in this system.

Large magnetoresistance in tunnel junctions with an iron oxide electrode

We report on the fabrication and properties of (cobalt/alumina/iron oxide) tunnel junctions. We observe magnetoresistance (MR) effects reaching 43% at 4.2 K and 13% at room temperature. This large MR is ascribed to the presence of a Fe3−xO4 (close to half-metallic magnetite) phase identified by electron diffraction. At low temperature, the MR drops sharply when the bias voltage is smaller than 10 mV, which suggests that the magnetoresistance originates from the activation of tunneling channels through spin polarized states below and above the Fermi level in the iron oxide.

High-Rate Capability Silicon Decorated Vertically Aligned Carbon Nanotubes for Li-Ion Batteries

The concept of a hybrid nanostructured collector made of thin vertically aligned carbon nanotubes (CNTs) decorated with Si nanoparticles provides high power density anodes in lithium-ion batteries. An impressive rate capability is achieved due to the efficient electronic conduction of CNTs combined with well defined electroactive Si nanoparticles: capacities of 3000 mAh g−1 at 1.3C and 800 mAh g−1 at 15C are achieved.

Enhancement of the magnetic anisotropy of nanometer-sized Co clusters: Influence of the surface and of interparticle interactions

We study the magnetic properties of spherical Co clusters with diameters between 0.8 nm and 5.2 nm (25\char21{}7000 atoms) prepared by sequential sputtering of Co and

On the mechanisms of precipitation of graphene on nickel thin films

{\mathrm{Al}}_{2}{\mathrm{O}}_{3}.

Perpendicular giant magnetoresistance of NiFe/Cu multilayered nanowires

The particle size distribution has been determined from the equilibrium susceptibility and magnetization data and it is compared with previous structural characterizations. The distribution of activation energies has been independently obtained from a scaling plot of the ac susceptibility. Combining these two distributions we have accurately determined the effective anisotropy constant

Magnetization reversal in cobalt and nickel electrodeposited nanowires

{K}_{\mathrm{eff}}.

Fast diffusers Cu and Ni as the origin of electrical activity in a silicon grain boundary

We find that

Synthesis of few-layered graphene by ion implantation of carbon in nickel thin films

{K}_{\mathrm{eff}}

Towards Two-Dimensional Metallic Behavior at LaAlO3/SrTiO3 Interfaces

is enhanced with respect to the bulk value and that it is dominated by a strong anisotropy induced at the surface of the clusters. Interactions between the magnetic moments of adjacent layers are shown to increase the effective activation energy barrier for the reversal of the magnetic moments. Finally, this reversal process is shown to proceed classically down to the lowest temperature investigated (1.8 K).