92 research outputs found
Effect of short range order on electronic and magnetic properties of disordered Co based alloys
We here study electronic structure and magnetic properties of disordered CoPd
and CoPt alloys using Augmented Space Recursion technique coupled with the
tight-binding linearized muffin tin orbital (TB-LMTO) method. Effect of short
range ordering present in disordered phase of alloys on electronic and magnetic
properties has been discussed. We present results for magnetic moments, Curie
temperatures and electronic band energies with varying degrees of short range
order for different concentrations of Co and try to understand and compare the
magnetic properties and ordering phenomena in these systems.Comment: 15 pages,17 postscript figures,uses own style file
DefectâDriven Magnetization Configuration of Isolated Linear Assemblies of Iron Oxide Nanoparticles
International audienceThe magnetization state of one-dimensional magnetic nanoparticle chains plays a key role for a wide range of applications ranging from diagnosis and therapy in medicine to actuators, sensors and quantum recording media. The interplay between the exact particle orientation and the magnetic anisotropy is in turn crucial for controlling the overall magnetization state with high precision. Here, we report on a three-dimensional description of the magnetic structure of one-NP-wide chains. In this aim, we combined two complementary experimental techniques, magnetic force microscopy (MFM) and electronic holography (EH) which are sensitive to out-of-plane and in-plane magnetization components, respectively. We extended our approach to micromagnetic simulations which provided results in good agreement with MFM and EH. The findings are at variance with the known results on unidirectional nanoparticle assemblies, and show that magnetization is rarely strictly collinear to the chain axis. The magnetic structure of one-NP-wide chains can be interpreted as head-to-head magnetic domain structures with off-axis magnetization components, which is very sensitive to morphological defects in the chain structure such as minute size variation of NPs, tiny misalignment of NPs and/or crystal orientation with respect to easy magnetization axis
Magnetic properties of X-Pt (X=Fe,Co,Ni) alloy systems
We have studied the electronic and magnetic properties of Fe-Pt, Co-Pt and
Ni-Pt alloy systems in ordered and disordered phases. The influence of various
exchange-correlation functionals on values of equilibrium lattice parameters
and magnetic moments in ordered Fe-Pt, Co-Pt and Ni-Pt alloys have been studied
using linearized muffin-tin orbital method. The electronic structure
calculations for the disordered alloys have been carried out using augmented
space recursion technique in the framework of tight binding linearized
muffin-tin orbital method. The effect of short range order has also been
studied in the disordered phase of these systems. The results show good
agreements with available experimental values.Comment: 21 pages, 4 eps figures, accepted for publication in Journal of
Physics Condensed Matte
Diffuse scattering
Diffuse neutron scattering covers a wide range of phenomena related to short range nuclear and magnetic orderings. Although it is âa prioriâ simple to measure, the underlying physics is often quite complex. Extracting useful and reliable information requires careful corrections and calibrations, and appropriate models of analysis, specifics for each physical case. This paper yields a partial and subjective glance on this specific subject, showing studies about chemical orderings in binary alloys and magnetic correlations in frustrated âspin icesâ as examples
Femmes et Physique, la commission reprend du service
La commission « Femmes et Physique » de la SociĂ©tĂ© Française de Physique a pour objectif dâattirer, dâencourager et de promouvoir les femmes dans les mĂ©tiers de la physique(1
SĂ©minaire âWomen in Scienceâ Ă Bangalore
Du 3 au 5 févier 2015 a eu lieu à Bangalore (Inde) un séminaire franco-indien « Femmes en
Sciences », soutenu par le CEFIPRA, et qui a réuni 250 participantes indiennes, 9
participantes françaises et une dizaine dâhommes. Le sĂ©minaire a mis en relief la science
faite par des femmes dans le cadre de collaborations franco-indiennes en mathématiques,
physique et biologie, et a Ă©tĂ© lâoccasion dâune table ronde sur le problĂšme des femmes en
sciences : comment le CEFIPRA peut-il aider à améliorer leur place, en Inde en
particulierÂ
- âŠ