Pr-doped YPO nanocrystal embedded into an optical fiber.

Optical fiber with YPO:Pr nanocrystals (NCs) is presented for the first time using the glass powder-NCs doping method. The method's advantage is separate preparation of NCs and glass to preserve luminescent and optical properties of NCs once they are incorporated into optical fiber. The YPO:Pr nanocrystals were synthesized by the co-precipitation and hydrothermal methods, optimized for size (< 100 nm), shape, Pr ions concentration (0.

Identifying the presence of magnetite in an ensemble of iron-oxide nanoparticles: a comparative neutron diffraction study between bulk and nanoscale.

Scientific interest in iron-oxides and in particular magnetite has been renewed due to the broad scope of their fascinating properties, which are finding applications in electronics and biomedicine. Specifically, iron oxide nanoparticles (IONPs) are gathering attraction in biomedicine. Their cores are usually constituted by a mixture of maghemite and magnetite phases.

Exploring the Different Degrees of Magnetic Disorder in TbRCu Nanoparticle Alloys.

Recently, potential technological interest has been revealed for the production of magnetocaloric alloys using Rare-Earth intermetallics. In this work, three series of TbxR1-xCu2 (R ≡ Gd, La, Y) alloys have been produced in bulk and nanoparticle sizes via arc melting and high energy ball milling. Rietveld refinements of the X-ray and Neutron diffraction patterns indicate that the crystalline structure in all alloys is consistent with TbCu2 orthorhombic Imma bulk crystalline structure.

Investigating the Size and Microstrain Influence in the Magnetic Order/Disorder State of GdCu Nanoparticles.

A series of GdCu 2 nanoparticles with controlled sizes ranging from 7 nm to 40 nm has been produced via high-energy inert-gas ball milling. Rietveld refinements on the X-ray diffraction measurements ensure that the bulk crystalline I m m a structure is retained within the nanoparticles, thanks to the employed low milling times ranging from = 0.5 to = 5 h.

Cryogenic study of the magnetic and thermal stability of retained austenite in nanostructured bainite.

First magnetic characterization of a recently developed generation of carbide free bainitic steels, known as Nanobain, has been performed. Stability of its retained austenite at cryogenic temperatures has been studied by means of X-ray diffraction, microscopy, dilatometry and magnetic measurements. Two morphologies for this phase (-type and -type) appear in a different proportion depending on the chemical composition and the applied thermal treatment.

Influence of clustering on the magnetic properties and hyperthermia performance of iron oxide nanoparticles.

Clustering of magnetic nanoparticles can drastically change their collective magnetic properties, which in turn may influence their performance in technological or biomedical applications. Here, we investigate a commercial colloidal dispersion (FeraSpinR), which contains dense clusters of iron oxide cores (mean size around 9 nm according to neutron diffraction) with varying cluster size (about 18-56 nm according to small angle x-ray diffraction), and its individual size fractions (FeraSpinXS, S, M, L, XL, XXL). The magnetic properties of the colloids were characterized by isothermal magnetization, as well as frequency-dependent optomagnetic and AC susceptibility measurements.

Breakdown of the coherence effects and Fermi liquid behavior in YbAl nanoparticles.

A change in the Kondo lattice behavior of bulk YbAl has been observed when the alloy is shaped into nanoparticles (≈12 nm). Measurements of the electrical resistivity show inhibited coherence effects and deviation from the standard Fermi liquid behavior (T -dependence). These results are interpreted as being due to the effect of the disruption of the periodicity of the array of Kondo ions provoked by the size reduction process.

Magnetic phase diagram of superantiferromagnetic TbCu₂ nanoparticles.

The structural state and static and dynamic magnetic properties of TbCu2 nanoparticles are reported to be produced by mechanical milling under inert atmosphere. The randomly dispersed nanoparticles as detected by TEM retain the bulk symmetry with an orthorhombic Imma lattice and Tb and Cu in the 4e and 8h positions, respectively. Rietveld refinements confirm that the milling produces a controlled reduction of particle sizes reaching ≃6 nm and an increase of the microstrain up to ≃0.

Revisited magnetic phase diagram for CeNi1-xCux system: spin-glass in the weak interaction limit.

We report the revisited magnetic phase diagram for the Kondo (ferromagnetic and antiferromagnetic) CeNi1−xCux series based on ac–dc magnetization, heat capacity, neutron diffraction and muon spectroscopy down to very low temperatures (~100 mK). An evolution from antiferromagnetism, observed for Cu-rich alloys (0.8 ≤ x ≤ 1), to clustered-ferromagnetism, seen for samples with 0.

Mesoscopic magnetic states in metallic alloys with strong electronic correlations: a percolative scenario for CeNi 1-x Cux.

We present evidence for the existence of magnetic clusters of approximately 20 A in the strongly correlated alloy system CeNi 1-x Cux (0.7 View Article and Find Full Text PDF

Size effects in the magnetic behaviour of TbAl(2) milled alloys.

The study of the magnetic properties depending upon mechanical milling of the ferromagnetic polycrystalline TbAl(2) material is reported. Rietveld analysis of the x-ray diffraction data reveals a decrease in the grain size down to 14 nm and a -0.15% variation in the lattice parameter, after 300 h of milling time.

Conserving the coherence and uniformity of third-generation synchrotron radiation beams: the case of ID19, a 'long' beamline at the ESRF.

The lateral coherence length is of the order of 100 micron at the 'long' (145 m) ID19 beamline of the ESRF, which is mainly devoted to imaging. Most of the optical elements located along the X-ray path can thus act as ;phase objects', and lead to spurious contrast and/or to coherence degradation, which shows up as an enhanced effective angular size of the source. Both the spurious contrast and the coherence degradation are detrimental for the images (diffraction topographs, tomographs, phase-contrast images) produced at this beamline.

Possible quantum critical point in La(2/3)Ca(1/3)Mn(1-x)Ga x O3.

We study the magnetic ground state in La(2/3)Ca(1/3)Mn(1-x)Ga x O3 manganites, where a quantum critical point (QCP) has been theoretically predicted. The metallic ferromagnetic ground state for low Ga doping breaks down for x > or = 0.11, an insulating state being established at low temperatures.