Magnetic properties and giant magnetoresistance in melt-spun CoCu alloys

Magnetic, structural, and transport properties of as quenched and annealed Co10Cu90 samples have been investigated using x¿ray diffraction and a SQUID magnetometer. The largest value of MR change was observed for the as¿quenched sample annealed at 450°C for 30 min. The magnetic and transport properties closely correlate with the microstructure, mainly with Co magnetic particle size and its distribution. For thermal annealing the as quenched samples below 600°C, the Co particle diameters increase from 4.0 to 6.0 nm with a magnetoresistance (MR) drop from 33.0% to 5.0% at 10 K. Comparison with the theory indicates that the interfacial electron spin¿dependent scattering mechanism correlates with GMR for Co particle diameters up to about 6.0 nm

Magnetic properties and giant magnetoresistance in melt‐spun Co‐Cu alloys

Magnetic, structural, and transport properties of as quenched and annealed Co10Cu90 samples have been investigated using x¿ray diffraction and a SQUID magnetometer. The largest value of MR change was observed for the as¿quenched sample annealed at 450°C for 30 min. The magnetic and transport properties closely correlate with the microstructure, mainly with Co magnetic particle size and its distribution. For thermal annealing the as quenched samples below 600°C, the Co particle diameters increase from 4.0 to 6.0 nm with a magnetoresistance (MR) drop from 33.0% to 5.0% at 10 K. Comparison with the theory indicates that the interfacial electron spin¿dependent scattering mechanism correlates with GMR for Co particle diameters up to about 6.0 nm

Subgrouping the autism "spectrum": reflections on DSM-5

DSM-5 has moved autism from the level of subgroups ("apples and oranges") to the prototypical level ("fruit"). But making progress in research, and ultimately improving clinical practice, will require identifying subgroups within the autism spectrum

Size constancy is preserved but afterimages are prolonged in typical individuals with higher degrees of self-reported autistic traits

Deficits in perceptual constancies from early infancy have been proposed to contribute to autism and exacerbate its symptoms (Hellendoorn et al., Frontiers in Psychology 6:1–16, 2015). Here, we examined size constancy in adults from the general population (N = 106) with different levels of self-reported autistic traits using an approach based on negative afterimages. The afterimage strength, as indexed by duration and vividness, was also quantified. In opposition to the Hellendoorn and colleagues’ model, we were unable to demonstrate any kind of relationship between abilities in size constancy and autistic traits. However, our results demonstrated that individuals with higher degrees of autistic traits experienced more persistent afterimages. We discuss possible retinal and post-retinal explanations for prolonged afterimages in people with higher levels of autistic traits

Some magnetic properties of dilute ferromagnetic alloys

Previous experiments (1955) have been carried out by the author on the magnetic properties of precipitates of dilute ferromagnetic alloys precipitated from solid solutions in non-ferromagnetic matrices. This process could be followed from the initial stages of superparamagnetism through single to multi-domain size of the aggregates, and the magnetic measurements correlated with particle growth. In the present communication, the work is extended to the production of precipitates in which departure from spherical shape is produced by cold drawing of suitable alloys. Magnetic measurements on the anisotropic specimens so produced are shown to give evidence for the distribution of particle shape, size and structure. The reverse magnetic field required to reduce the remanence to zero is shown to be an additional useful parameter in these determinations. Microphotographs of the samples showed that in all three cases the precipitates of the specimens of maximum coercivity were larger than would have been expected from single domain particles. Experiments are being continued.L'auteur avait déjà fait, en 1955, des expériences dans le domaine des propriétés magnétiques d'alliages ferromagnétiques dilués, précipités de solutions solides dans des matrices non-ferromagnétiques. Ce processus a pu être suivi depuis l'état initial superparamagnétique jusqu'à la formation d'agrégats monodomaines et multidomaines, et les mesures magnétiques ont pu être mises en relation avec la croissance des particules. Au cours des travaux exposés, le champ des recherches a été étendu par la production de précipités où des déviations de la forme sphérique sont provoquées par étirage à froid d'alliages appropriés. Les mesures magnétiques prises sur les spécimens ainsi obtenus sont susceptibles de démontrer la distribution de forme, de dimension et de structure des particules. U est démontré que le champ magnétique inverse nécessaire pour annuler la rémanence peut constituer un paramètre supplémentaire utile. Des microphotographies des spécimens démontrèrent que, dans les trois cas étudiés, les précipités des spécimens de coercivité maxima étaient plus grands que ceux que l'on pourrait compter obtenir de particules à domaine simple. Les expériences se poursuivent

Magnetic saturation intensity and some other related measurements

Dans la première Partie, l'auteur attire l'attention sur le fait que des mesures exactes de l'aimantation spontanée n'ont été effectuées que dans un très petit nombre de cas. Les résultats pour le cobalt, qui possède un réseau hexagonal jusqu'au point de Curie et un réseau cubique centré au-dessus, sont donnés et discutés. Une augmentation de 1,5 pour 100 se produit à la température de transition. Dans la deuxième Partie, la variation de l'aimantation à saturation et le degré de l'ordre dans quelques alliages binaires sont donnés. Dans la dernière Partie, on montre l'importance des mesures de l'aimantation à saturation pour étudier la détermination de l'équilibre des phases. L'auteur cite l'application heureuse de cette méthode au cas du système fer-carbone, caractérisé par quelques phases qui ne figurent pas à l'état d'équilibre