Current perpendicular to the plane, giant magnetoresistance (GMR) and the spin-valve effect were observed in Co/Cu multilayered nanowires electrodeposited into self-organized nanoporous anodized aluminium templates grown at the surface of bulk aluminium. Pores as short as 2000 nm could be used. The pore bottom oxide layer was removed or thinned by chemical etching. Alternating Co and Cu layers of 10 nm in thickness were synthesized by pulse plating. 20% of GMR was observed in 100 Co/Cu bilayer nanowires at room temperature. Co/Cu/Co tri-layered nanowires clearly showed the typical resistance switching of spin-valves.

Magnetization reversal triggered by spin injection is measured in electrodeposited Co/Cu/Co pillars (diameter about 60 nm). Two protocols are used. (i) switching of magnetization after a current pulse is monitored as a function of applied field. The maximum offset from the switching field at which irreversible switching occurs is a measure of the strength of the effect; and (ii) irreversible and reversible magnetization changes are observed while the current is ramped at fixed applied field. (i) and (ii) show that irreversible transitions occur only from antiparallel to parallel magnetic configurations and for electrons flow from the polarizer to the analyzer.

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Nanopores with a wide range of aspect ratios were fabricated in an anodized aluminium oxide layer on bulk metallic aluminium. The aspect ratios (L/D) were around 20–1000 (pore length, L, 1000–60 000 nm; pore diameter, D, 50–100 nm). For comparison, nanopores in polymer films were also prepared using heavy-ion-track etched polyimide films (L, 70 000 nm; D, 70 nm; L/D = 1000) and polycarbonate films (L, 30 000 nm; D, 100 nm; L/D = 300). The pore diameter of the anodized aluminium oxide layer was controlled by the anodization voltage, while the pore diameter of the heavy-ion-tracked polyimide and polycarbonate films was controlled by the etching time in a sodium hydroxide alkaline solution. Ni and Co homogeneous single nanowires were fabricated using the electrodeposition and in situ contacted techniques in the nanoporous templates. The Ni and Co nanowires with the largest aspect ratios (L/D = 1000) showed around 2.3% and 1.6% of the typical anisotropic magnetoresistance (AMR), and the effects of aspect ratio on the resistance and AMR were investigated.

The direct effect of spin-polarized current on magnetization states is studied on various electrodeposited single contacted nanowires (diameter about 60 nm). Three kinds of samples have been studied: (1) Homogeneous Ni nanowires, (2) nanowires composed of both a homogeneous Ni part and a multilayered Co(10 nm)/Cu(10 nm) part, (3) pseudospin-valve pillars Co(30 nm)/Cu(10 nm)/Co(10) electrodeposited in Cu wires. The magnetization reversal due to the current injection is observed in the three cases. The effect is observed with using different experimental protocols, including current activated after-effect measurements. The results obtained suggest that two different mechanisms are able to account for the magnetization reversal: exchange torque and spin transfer. We propose a definition of the two mechanisms based on the conservation or nonconservation of the magnetic moment of the ferromagnetic nanostructure.