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Nickel nanowires prepared by electrochemical growth in alumina templates have been removed from their templates and functionalized with luminescent porphyrins. The nanowires response to magnetic fields was quantified using video microscopy. In viscous solvents, magnetic fields can be used to orient the nanowires; in mobile solvents, the nanowires form chains in a head-to-tail configuration when a small magnetic field is applied. The dynamics for chain formation have been quantitatively modeled. The results demonstrate a new approach for assembling nanowires.

The etching of the more active component from a homogeneous alloy is important in corrosion reactions and has been exploited in the synthesis of high surface area nanoporous materials. In this paper we show that nanoporous films can be obtained by selective electrochemical etching of the more noble component in a system where the more active component is passivated. We demonstrate that nanoporous nickel films can be obtained by a two-step process involving electrodeposition of a homogeneous Ni x Cu 1-x alloy followed by electrochemical etching of the copper from the alloy. The composition, lattice parameter, saturation magnetization, and Curie temperature of the electrodeposited Ni x Cu 1-x alloys can be precisely controlled by varying the deposition conditions. Nanoporous nickel can be formed by electrochemically etching the copper from the alloy. The nanoporous structures are characterized by a three-dimensional network of interconnected pores and exhibit enhanced coercivity and reduced magnetic anisotropy. The morphology of the nanoporous nickel films is dependent on the initial composition of the Ni x Cu 1-x alloy.

Thin Pt films on an yttrium iron garnet (YIG = Y(3)Fe(5)O(12)) show ferromagneticlike transport properties, which may impact the functionality of Pt in spin current detection, but do not provide direct quantitative information on the Pt magnetization. We report magnetic x-ray magnetic circular dichroism measurements of YIG/Pt(1.5 nm) showing an average Pt moment of 0.054 μ(B) at 300 K and 0.076 μ(B) at 20 K. This observation indicates strong proximity effects and induced magnetic ordering in Pt on magnetic insulators and their contribution to the spin-related measurements should not be neglected. The transport characteristics also suggest considerable modifications in the Pt electronic structure due to magnetic ordering.

By systematically comparing the magnetic properties of the Ta/CoFeB/Ta and MgO/CoFeB/MgO structures with and without a submonolayer of MgO, Ta, V, Nb, Hf and W inserted in the middle of the CoFeB layer, we have proved that the observed perpendicular magnetic anisotropy (PMA) in Ta/CoFeB/MgO sandwiches is solely originated from the CoFeB/MgO interface with the Ta buffer acting to enhance the CoFeB/MgO interface anisotropy significantly. Moreover, replacing Ta with Hf causes the CoFeB/MgO interfacial PMA further enhanced by 35%, and the CoFeB layer with perpendicular magnetization has a much larger critical thickness accordingly, leaving a wider thickness margin for the CoFeB/MgO-based perpendicular magnetic tunnel junction optimization. Also the sputter deposited thin Hf films are amorphous with low surface roughness. These results will ensure the Hf/CoFeB/MgO more promising material system for PMA device development.