Conduction a deux bandes et effet de periode dans les alliages a base de nickel et de cobalt

Magnetic behaviour of Co-Cr alloys above the critical concentration for ferromagnetism

“…-Magnetization measurements performed on dilute Co-Cr alloys have shown that the variation d7p/dc of the average magnetic moment with the chromium concentration is as high as - 6.6pB [1,2]. This and other physical properties [3,4], have been interpreted as the occurrence of a virtual bound state above the Fermi level. However a recent calculation of the band structure of the Ni-Cr dilute alloy [5] shows that the density of states or the majority spin electrons on the impurity site not only consists of the virtual bound state but also extends over the whole d band of the matrix which lies below the Fermi level.…”

Abstract: Form factor and moment distribution in Ni0.97Ru0.03 alloy by polarised neutrons

“…These U-moments, which are respectively 1.8 and 1.4 ~B at 4.2 K in the Co and Fe case, fall rapidly under .S ~B when the temperature is raised and remain small until Tc. But when, in FeU2SS, this drop takes place sharply around 20 K with a change of the magnetic structure, it is more regular in CoU2SS with no significant change of the moment's directions from 4.2 K up to Tc' The behavior of CoU2SS powder samples in high magnetic fields is very similar to that of CrUS3 with very large threshold fields to move the ferromagnetic domain walls and related after-effects [2). Furthermore, in both compounds, the observed spontaneous magnetization on powder samples is very close to half the ferromagnetic component determined by neutron diffraction.…”

Fabrication and Characterization of In0.25Ga0.75N/GaN Multiple Quantum Wells Embedded in Nanorods

“…For nickel alloys in particular a number of investigators (Fert and Campbell 1968, 1971, Durand and Gautier 1970. Farrell and Greig 1968 have successfully interpreted their experimental data.…”