Magnetic and Magnetoresistive Properties of 3D Interconnected NiCo Nanowire Networks

Abstract

Track-etched polymer membranes with crossed nanochannels have been revealed to be most suitable as templates to produce large surface area and mechanically stable 3D interconnected nanowire (NW) networks by electrodeposition. Geometrically controlled NW superstructures made of NiCo ferromagnetic alloys exhibit appealing magnetoresistive properties. The combination of exact alloy compositions with the spatial arrangement of NWs in the 3D network is decisive to obtain specific magnetic and magneto-transport behavior. A proposed simple model based on topological aspects of the 3D NW networks is used to accurately determine the anisotropic magnetoresistance ratios. Despite of their complex topology, the microstructure of Co-rich NiCo NW networks display mixed fcc-hcp phases with the c-axis of the hcp phase oriented perpendicular to their axis. These interconnected NW networks have high potential as reliable and stable magnetic field sensors.

Magnetic Nanowires

“…Hereafter, the as-prepared polymer membranes containing networks of interconnected cylindrical nanopores were designed with pores of well-defined diameters between 40 and 230 nm and with different porosity characteristics (P = 3% and P = 20%, with P the void volume fraction of the membrane). Next, the template-assisted electrodeposition method was used for the synthesis of well-defined 3D architecture consisting of crossed nanowire (CNW) and nanotube (CNT) networks [60][61][62][63]66]. In addition, magnetic and non-magnetic layers were electrochemically stacked to make interconnected multilayered nanowires [64,65,67].…”

“…The research activity at UCLouvain on magnetic NWs were also motivated by related applications in microwave devices [46][47][48][49][50][51][52][53][54] and multiferroic nanocomposites [55][56][57][58][59]. Recently, we demonstrated the suitability of three-dimensional (3D) nanoporous polymer templates to form dense interconnected magnetic NW networks with tunable geometrical parameters in terms of nanowire size, density, and orientation opens up the possibility for a controlled synthesis of a large variety of complex 3D networks of high aspect-ratio nanostructures with different geometries and materials [60][61][62][63][64][65][66][67]. Their unique architectures and high degree of nanowire interconnectivity facilitate the ability to perform magneto-transport measurements and to investigate the interplay between electronic and thermoelectric transport and magnetic properties.…”

Metal Nanotube/Nanowire-Based Unsupported Network Electrocatalysts

“…Electrodeposition is inclined to fill up the template pores starting from the bottom of an electrical contact layer on one side of the template membrane, and thus, usually yields 3D nanowire networks ( Figure 8B-D), which have been prepared from different metals and metal combinations (e.g., Pt [2,90], Ni [103,104], and Ni alloys containing Fe/Co [104][105][106]). Crossing core-shell nanowires can be selectively etched out to obtain nanotube networks, as was demonstrated for Cu-Ni nanocables [107].…”

“…What makes ion-track templated nano-networks special is the structural control, including the degree of order and the high level of porosity that can be achieved. Ordered nano-networks are particularly interesting for applications which exploit properties stemming from the anisotropy and the specific mutual alignment of the 1D building blocks (e.g., magnetism [104][105][106][107]). While ion-track membranes lack the periodicity of other template variants, this aspect is far less important for constructing efficient catalysts than the ability to widely adjust the overall network architecture and porosity [118], in which they excel.…”

Ni-Co Alloy and Multisegmented Ni/Co Nanowire Arrays Modulated in Composition: Structural Characterization and Magnetic Properties

“…Among the solid template-based growth methods, the template-assisted electrochemical deposition of single metals and their alloys is one of the most efficient and versatile growing technique popularly employed for the synthesis of 1D nanomaterials embedded inside the pores of polymeric or anodic aluminum oxide (AAO) membranes [16][17][18][19]. The synthesis of nanomaterials through the template-assisted electrodeposition method by employing nanoporous alumina membranes (NAMs) as patterned templates, is a commonly used technique for the growing of metallic and magnetic nanostructures inside the pores of anodic alumina with a wire shape geometry and in the nanometer scale range (typically between 20 to 200 nm in diameter size) [20,21].…”