Magnetic and Superconducting Nanowires

Abstract

This article is focused on the use of electrodeposition and of various nanoporous templates for the fabrication of metallic nanowires made from single metals (Ni, Co, Pb, Sn), alloys (NiFe, CoFe, CoPt), and multilayers (Co/Cu, NiFe/Cu). An overview is given of our recent studies performed on both magnetic and superconducting nanowires. Using different approaches entailing measurements on both single wires and arrays, numerous interesting physical properties have been identified in relation to the nanoscopic dimensions of these materials. Finally, various novel applications of the nanowires are also discussed.

Configuration dependent demagnetizing field in assemblies of interacting magnetic particles

“…Full details of the preparation process can be found elsewhere. 21 For the electrodeposition a Cr/Au layer is evaporated previously on one side of the membrane to serve as a cathode and deposition is done at a constant potential using a Ag/AgCl reference electrode. For CoFe a 40 g/l FeSO 4 + 80 g/l CoSO 4 + 30 g/l H 3 BO 3 electrolyte was used with a potential of V =-0.9 V, while for NiFe the electrolyte contained 5.6 g/l FeSO 4 + 131.4 g/l NiSO 4 + 30 g/l H 3 BO 3 and deposition is done at V =-1.1 V. Cobalt nanowires have been grown at V =-1V using a 238.5 g/l CoSO 4 + 30 g/l H 3 BO 3 electrolyte with the pH set to 2.0 by addition of H 2 SO 4 to favor a polycrystalline fcc-like Co structure with no magnetocrystalline anisotropy contribution.…”

“…18,21,22 For all the samples considered, the transmission spectra is recorded at a fixed frequency while the magnetic field is swept from 10 down to 0 kOe. These measurements are repeated for different frequencies and from the collection of frequencies and their respective resonance field, the dispersion relation is obtained.…”

Electrodeposited magnetic layers in the ultrathin limit

“…Penner et al developed very nice applications of ED to grow arrays of wires with specific applications. 50 Magnetic nanowires also have been obtained by ED inside insulating nanoporous membranes 51 and porous magnetic fi lms by ED inside a monolayer of self-assembled polystyrene beads. 52 Nanostructures can be obtained in UHV 53,54 or at the electrochemical interface 10 by selective decoration of surface defects.…”

Fabrication of Quasi-One-Dimensional Superconducting Micro- and Nanostructures

“…On the contrary, chemical or electrochemical methods allow filling of very narrow pores with a vide variety of materials including superconductors: Pb [32,33], Sn [33][34][35][36] and Zn [37,38]. The most widely used media are tracketched membranes and alumina nanoporous films [39]. The diameter of pores in these materials can be rather uniform ranging from ~ 15 nm to few μm.…”