Showing papers by "Albert Fert published in 1994"

Giant magnetoresistance in magnetic multilayered nanowires

Abstract: Giant magnetoresistance (GMR) is observed in a new type of nanostructured material consisting of magnetic multilayered nanowires formed by electrodeposition into nanometer-sized pores of a template polymer membrane. The composition of these nanowires is modulated over nanometer length scales with distinct magnetic and nonmagnetic metallic layers. Magnetoresistance measurements with the current perpendicular to the layers were performed on the array of parallel nanowires. GMR of about 15% was observed at room temperature on Co/Cu multilayered nanowires. (C) 1994 American Institute of Physics.

Inverse spin-valve-type magnetoresistance in spin engineered multilayered structures.

Abstract: The resistivity of magnetic multilayers is generally smaller when the magnetizations of successive layers are parallel, which is the so-called giant magnetoresistance or spin-valve effect. %'e have been able to reverse this eA'ect and to obtain a smaller resistivity for an antiparallel arrangement by intercalating thin Cr layers within half of the Fe layers in Fe/Cu multilayers. This inverse spin-valve elfect is due to the inverse spin asymmetries of the electron scattering in successive Fe layers with and without Cr. This is a confirmation of the fundamental mechanism of the giant magnetoresistance.

Calculation of the temperature dependence of the giant mr and application to Co/Cu multilayers

Abstract: Most theoretical models of the giant magnetoresistance (GMR) in metallic magnetic multilayers developed up to now are for the zero‐temperature limit, thus neglecting the spin‐flip scattering arising from spin fluctuations (magnons), as well as other scatterings from thermal excitations. To account for the temperature dependence of the GMR, we have introduced electron–magnon and electron–phonon scattering terms in a Camley–Barnas‐like semi‐classical model. We apply our calculation to the interpretation of the temperature dependence of the resistivity and GMR in Co/Cu.

Perpendicular magnetoresistance in magnetic multilayers: Theoretical model and discussion (invited)

Abstract: After a general introduction describing the mechanisms of the current perpendicular to the layer plane magnetoresistance (CPP‐MR), a microscopic model based on the Boltzmann equation is presented and a general expression of the magnetoresistance is derived in which the spin diffusion length appears as the unique scaling length of the problem. In the limit where the spin diffusion lengths are much larger than the layer thicknesses, the expression of the CPP‐MR becomes very simple and similar to that already used at Michigan State University for the analysis of experimental results. Out of this limit, the model predicts a dramatic reduction of the CPP‐MR if the spin diffusion lengths are shortened sufficiently by paramagnetic impurities or spin‐orbit scatterers. Finally, a calculation is presented of the spin‐dependent interface resistances involved in the model and related to interface potential steps, and experimental data are compared.

Giant steps with tiny magnets

Abstract: When a metal or semiconductor is placed in a magnetic field, its electrical resistivity usually increases by a small amount. This phenomenon, known as magnetoresistance, can be readily explained in terms of the Lorentz force acting on the electrons carrying the electric current. Six years ago a remarkable new form of this familiar effect – "giant magnetoresistance" – was discovered, and this has been the subject of intense research and development ever since. Besides being an intriguing puzzle in fundamental condensed matter physics, giant magnetoresistance (GMR) also has obvious applications in the magnetic recording industry where it offers the promise of much greater information storage densities than those available at present.