Crystal structure and magnetic properties of some MM’X pnictides investigated by neutron diffraction and magnetisation measurements

In order to analyse the magnetic structure and to point out potential relationships between the structural parameters and magnetic behaviour, an in situ powder diffraction experiments were investigated for three specific compounds and systems MM'X. The study was carried out also by using magnetisation measurements. These investigations are supported by electronic structural calculations analyses carried out in parallel to this work.In order to analyse the magnetic structure and to point out potential relationships between the structural parameters and magnetic behaviour, an in situ powder diffraction experiments were investigated for three specific compounds and systems MM'X. The study was carried out also by using magnetisation measurements. These investigations are supported by electronic structural calculations analyses carried out in parallel to this work

A Nonaqueous Approach to the Preparation of Iron Phosphide Nanowires

Previous preparation of iron phosphide nanowires usually employed toxic and unstable iron carbonyl compounds as precursor. In this study, we demonstrate that iron phosphide nanowires can be synthesized via a facile nonaqueous chemical route that utilizes a commonly available iron precursor, iron (III) acetylacetonate. In the synthesis, trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO) have been used as surfactants, and oleylamine has been used as solvent. The crystalline structure and morphology of the as-synthesized products were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The obtained iron phosphide nanowires have a typical width of ~16 nm and a length of several hundred nanometers. Structural and compositional characterization reveals a hexagonal Fe2P crystalline phase. The morphology of as-synthesized products is greatly influenced by the ratio of TOP/TOPO. The presence of TOPO has been found to be essential for the growth of high-quality iron phosphide nanowires. Magnetic measurements reveal ferromagnetic characteristics, and hysteresis behaviors below the blocking temperature have been observed

Ab initio studies of the electronic structure induced by the CO and N2 adsorptions on graphene and on graphite slab

International audienc

Modeling and simulation of complex flows using Basset digital filters

Taking into account the Basset force (memory term), in the balance of the forces exerted on a colloidal particle (CP) suspended in a fluid, results in an equation of motion of integrodifferential form. This type of equation allows for example to modeling a colloidal particle settling in an quiescent fluid or in a fluid flowing at low particle’s Reynolds number. It also allows to study the transport of pathogens via aerosols, thus giving access to important information on the airborne propagation of respiratory viruses, such as COVID-19 and its variants for example. Most studies of the PCs motion in a fluid are usually simplified by not taking into account the Basset memory force, as it considerably complicates the numerical solution of the equations of motion of these PCs. This simplification can lead to considerable errors in the evaluation of the trajectory and velocity of the PCs, which can subsequently lead to errors in the calculation of the physical and rheological properties of colloidal suspensions. The present study deals with the numerical solution of Basset’s integro-differential equation, by two significantly different approaches, namely : a piecewise linear approximation (PLA) and the method of Basset numerical filters (BNF). These methods are first exposed and compared on test cases, they are then applied to the study of the sedimentation of spherical PCs with micrometer radii. This study has shown that the usual dynamics of PCs, which does not take into account the Basset memory term, can be very different from the exact dynamics using the Basset force. The BNF approach is finally applied to the study of the motion of PCs driven by flows through complex geometries (pipes, porous media, …)

Critical behavior near the ferromagnetic to paramagnetic phase transition temperature in polycrystalline La0.7Ca0.2Sr0.1Mn1−xCrxO3 (x=0.15 and 0.2)

International audienc

On the magnetocaloric effect in d-metal pnictides

International audienc

On the magnetic effect in d-metal pnictides

International audienc

Critical behavior near the ferromagnetic to paramagnetic phase transition temperature in polycrystalline La0.7Ca0.2Sr0.1Mn1−Cr O3 (x= 0.15 and 0.2)

International audienc