Dimensionality-driven metal-insulator transition in spin-orbit-coupled IrO.

A metal-insulator transition is observed in spin-orbit-coupled IrO thin films upon reduction of the film thickness. In the epitaxially grown samples, the critical thickness ( ∼ 1.5-2.

Structural determination of Bi-doped magnetite multifunctional nanoparticles for contrast imaging.

To determine with precision how Bi atoms are distributed in Bi-doped iron oxide nanoparticles their structural characterization has been carried out by X-ray absorption spectroscopy (XAS) recorded at the K edge of Fe and at the L3 edge of Bi. The inorganic nanoparticles are nominally hybrid structures integrating an iron oxide core and a bismuth oxide shell. Fe K-edge XAS indicates the formation of a structurally ordered, non-stoichiometric magnetite (Fe3-δO4) phase for all the nanoparticles.

Competing effects in the magnetic polarization of non-magnetic atoms.

The magnetic polarization of the Lu 5d states through the Ho(1-x)Lu(x)(Fe(1-y)Al(y))(2) series has been studied by means of x-ray magnetic circular dichroism. A combined study of the dichroic signals performed at the Fe K-, Ho L(2)- and Lu L(2,3)-edges gives a complete picture of the polarization scheme at the conduction band. The results show that in the presence of competing localized magnetic moments, μ(Fe)(3d) and μ(Ho)(4f), the dichroic signal at the Lu site is mainly due to the Fe atoms, the effect of the magnetic rare-earth being negligible.

Surface functionalization for tailoring the aggregation and magnetic behaviour of silica-coated iron oxide nanostructures.

We report here a detailed structural and magnetic study of different silica nanocapsules containing uniform and highly crystalline maghemite nanoparticles. The magnetic phase consists of 5 nm triethylene glycol (TREG)- or dimercaptosuccinic acid (DMSA)-coated maghemite particles. TREG-coated nanoparticles were synthesized by thermal decomposition.

Size-dependent properties of magnetoferritin.

We report a detailed experimental study of maghemite nanoparticles, with sizes ranging from 1.6 to 6 nm, synthesized inside a biological mould of apoferritin. The structural characterization of the inorganic cores, using TEM and x-ray diffraction, reveals a low degree of crystalline order, possibly arising from the nucleation and growth of multiple domains inside each molecule.