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.

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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.

Cylindrical nano-pores of an anodized aluminum oxide layer on the surface of bulk aluminum were used as templates for the electrochemical growth of semiconductor and magnetic nanowires. The electrodeposition of CdTe and NiFe was investigated to determine the optimum conditions for each nanowire growth over a wide range of cathode potentials. The desired composition of Cd 50 Te 50 and Ni 80 Fe 20 was achieved by controlling the cathode potential during electrodeposition. Temperature dependences of resistance for CdTe nanowires confirmed the semiconductor character with amorphous behavior at low temperature, while those of NiFe nanowires showed metallic character. The anisotropic magnetoresistance (AMR) of NiFe nanowires reached 1.9% at 300 K.

Direct CD4þ T lymphocytes were separated from whole mouse splenocytes using 1-dimensional ferromagnetic nickel silicide nanowires (NiSi NWs). NiSi NWs were prepared by silver-assisted wet chemical etching of silicon and subsequent deposition and annealing of Ni. This method exhibits a separation efficiency of $93.5%, which is comparable to that of the state-of-the-art superparamagnetic bead-based cell capture ($96.8%). Furthermore, this research shows potential for separation of other lymphocytes, B, natural killer and natural killer T cells, and even rare tumor cells simply by changing the biotin-conjugated antibodies. Silicides are widely used as metal contact materials in modern silicon microelectronics because of their low contact resistivity and the excellent junction interface on silicon (Si).1,2 With the recent improvement in nanoscale Si devices, metal silicides have received significant attention because of their unique properties and potential applications in electronic and photonic devices.2-4 Recently, several research groups have studied nickel silicide nanowires (NiSi NWs).3,5-8 They confirmed that NiSi NWs show lower resistivity when formed at lower processing temperature with less reaction phase at interface compared to other metallic silicide materials. As a result, NiSi NWs are considered a promising material for use as gate and source/drain electrodes in current complementary metal oxide semiconductor devices.

A nano-porous anodized aluminum oxide layer was synthesized on the surface of bulk aluminum at a wide range of anodization voltages. The barrier layer at the pore bottom of anodized aluminum oxide layer was chemically etched to make good electrical contact for nanowires electrodeposited in the pores thus formed on metallic aluminum substrates.Cathodic polarization was examined at a wide range of cathode potentials to investigate the electrodeposition behavior of Cu and Co into the pores. Co 81 Cu 19 /Cu multilayered nanowires were fabricated using a pulse-plating technique into the templates. Co-alloy layer and Cu layer thicknesses were adjusted to 10nm, by controlling the deposition times. The temperature dependence of the resistance of Co 81 Cu 19 /Cu multilayered nanowires grown on the template presented clean metallic characteristics and a giant magnetoresistance (GM R) of 23% was reached at 4K.

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Polycarbonate templates of (30±1) µm thickness containing cylindrical etched-track nanochannels of (500±50) nm diameter were used for electrodeposition of Ni nanowires. Using 10 4 channels per cm 2 , the most favorable deposition potential of -1.0 V was determined in a potentiostatic mode by varying the deposition potential with respect to an Ag/AgCl reference electrode over a range between -0.1 V and -1.5 V. The deposition efficiency at -1.0 V was estimated around 10 %. The resulting single wires had a resistance around 200 Ω and showed an anisotropic magnetoresistance (AMR) effect of 1 %, applicable to directionally sensitive magnetic field sensors.