Magneto-Transport in Flexible 3D Networks Made of Interconnected Magnetic Nanowires and Nanotubes

Electrochemical deposition of interconnected nanowires and nanotubes made of ferromagnetic metals into track-etched polycarbonate templates with crossed nanochannels has been revealed suitable for the fabrication of mechanically stable three-dimensional magnetic nanostructures with large surface area. These 3D networks embedded into flexible polymer membranes are also planar and lightweight. This fabrication technique allows for the control of the geometric characteristics and material composition of interconnected magnetic nanowire or nanotube networks, which can be used to fine-tune their magnetic and magneto-transport properties. The magnetostatic contribution to the magnetic anisotropy of crossed nanowire networks can be easily controlled using the diameter, packing density, or angle distribution characteristics. Furthermore, the fabrication of Co and Co-rich NiCo alloy crossed nanowires with textured hcp phases leads to an additional significant magnetocrystalline contribution to the magnetic anisotropy that can either compete or add to the magnetostatic contribution. The fabrication of an interconnected nanotube network has also been demonstrated, where the hollow core and the control over the tube wall thickness add another degree of freedom to control the magnetic properties and magnetization reversal mechanisms. Finally, three-dimensional networks made of interconnected multilayered nanowire with a succession of ferromagnetic and non-magnetic layers have been successfully fabricated, leading to giant magnetoresistance responses measured in the current-perpendicular-to-plane configuration. These interconnected nanowire networks have high potential as integrated, reliable, and stable magnetic field sensors; magnetic devices for memory and logic operations; or neuromorphic computing.

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Giant Magnetoresistance and Magneto-Thermopower in 3D Interconnected NixFe1−x/Cu Multilayered Nanowire Networks

Nanomaterials ◽

10.3390/nano11051133 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1133

Author(s):

Nicolas Marchal ◽

Tristan da Câmara Santa Clara Gomes ◽

Flavio Abreu Araujo ◽

Luc Piraux

Keyword(s):

Giant Magnetoresistance ◽

Nanowire Array ◽

Three Dimensional ◽

Strong Increase ◽

Thermoelectric Effect ◽

Heat Management ◽

Thermoelectric Effects ◽

Nanowire Network ◽

Potential Applications ◽

Nanowire Networks

The versatility of the template-assisted electrodeposition technique to fabricate complex three-dimensional networks made of interconnected nanowires allows one to easily stack ferromagnetic and non-magnetic metallic layers along the nanowire axis. This leads to the fabrication of unique multilayered nanowire network films showing giant magnetoresistance effect in the current-perpendicular-to-plane configuration that can be reliably measured along the macroscopic in-plane direction of the films. Moreover, the system also enables reliable measurements of the analogous magneto-thermoelectric properties of the multilayered nanowire networks. Here, three-dimensional interconnected NixFe1−x/Cu multilayered nanowire networks (with 0.60≤x≤0.97) are fabricated and characterized, leading to large magnetoresistance and magneto-thermopower ratios up to 17% and −25% in Ni80Fe20/Cu, respectively. A strong contrast is observed between the amplitudes of magnetoresistance and magneto-thermoelectric effects depending on the Ni content of the NiFe alloys. In particular, for the highest Ni concentrations, a strong increase in the magneto-thermoelectric effect is observed, more than a factor of 7 larger than the magnetoresistive effect for Ni97Fe3/Cu multilayers. This sharp increase is mainly due to an increase in the spin-dependent Seebeck coefficient from −7 µV/K for the Ni60Fe40/Cu and Ni70Fe30/Cu nanowire arrays to −21 µV/K for the Ni97Fe3/Cu nanowire array. The enhancement of the magneto-thermoelectric effect for multilayered nanowire networks based on dilute Ni alloys is promising for obtaining a flexible magnetic switch for thermoelectric generation for potential applications in heat management or logic devices using thermal energy.

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A study of control growth of three-dimensional nanowire networks of tungsten oxides: From aligned nanowires through hybrid nanostructures to 3D networks

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2009.11.036 ◽

2010 ◽

Vol 312 (4) ◽

pp. 520-526 ◽

Cited By ~ 17

Author(s):

Z.L. Li ◽

Fei Liu ◽

N.S. Xu ◽

Jun Chen ◽

S.Z. Deng

Keyword(s):

Three Dimensional ◽

Hybrid Nanostructures ◽

Tungsten Oxides ◽

Control Growth ◽

Nanowire Networks ◽

3D Networks

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ZnO Nanowire Networks as Photoanode Model Systems for Photoelectrochemical Applications

Nanomaterials ◽

10.3390/nano8090693 ◽

2018 ◽

Vol 8 (9) ◽

pp. 693 ◽

Cited By ~ 9

Author(s):

Liana Movsesyan ◽

Albert Maijenburg ◽

Noel Goethals ◽

Wilfried Sigle ◽

Anne Spende ◽

...

Keyword(s):

Anatase Phase ◽

Three Dimensional ◽

Atomic Layer ◽

Model Systems ◽

Zno Nanowire ◽

Chemical Corrosion ◽

Tio2 Nanowire ◽

Nanowire Network ◽

Nanowire Networks ◽

3D Networks

In this work, the fabrication of zinc oxide (ZnO) nanowire networks is presented. By combining ion-track technology, electrochemical deposition, and atomic layer deposition, hierarchical and self-supporting three-dimensional (3D) networks of pure ZnO- and TiO2-coated ZnO nanowires were synthesized. Analysis by means of high-resolution transmission electron microscopy revealed a highly crystalline structure of the electrodeposited ZnO wires and the anatase phase of the TiO2 coating. In photoelectrochemical measurements, the ZnO and ZnO/TiO2 nanowire networks, used as anodes, generated higher photocurrents compared to those produced by their film counterparts. The ZnO/TiO2 nanowire network exhibited the highest photocurrents. However, the protection by the TiO2 coatings against chemical corrosion still needs improvement. The one-dimensionality of the nanowires and the large electrolyte-accessible area make these 3D networks promising photoelectrodes, due to the improved transport properties of photogenerated charge carriers and faster redox reactions at the surface. Moreover, they can find further applications in e.g., sensing, catalytical, and piezoelectric devices.

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Magnetization dynamics of irradiation-fabricated perpendicularly magnetized dots inside a softer magnetic matrix

MRS Proceedings ◽

10.1557/proc-777-t6.4 ◽

2003 ◽

Vol 777 ◽

Cited By ~ 2

Author(s):

T. Devolder ◽

M. Belmeguenai ◽

C. Chappert ◽

H. Bernas ◽

Y. Suzuki

Keyword(s):

Domain Wall ◽

Magnetic Anisotropy ◽

Magnetization Reversal ◽

Ion Irradiation ◽

Magnetic Nanostructures ◽

Magnetic Storage ◽

Exchange Field ◽

Static Magnetization ◽

Specific Domain ◽

Helium Ion

AbstractGlobal Helium ion irradiation can tune the magnetic properties of thin films, notably their magneto-crystalline anisotropy. Helium ion irradiation through nanofabricated masks can been used to produce sub-micron planar magnetic nanostructures of various types. Among these, perpendicularly magnetized dots in a matrix of weaker magnetic anisotropy are of special interest because their quasi-static magnetization reversal is nucleation-free and proceeds by a very specific domain wall injection from the magnetically “soft” matrix, which acts as a domain wall reservoir for the “hard” dot. This guarantees a remarkably weak coercivity dispersion. This new type of irradiation-fabricated magnetic device can also be designed to achieve high magnetic switching speeds, typically below 100 ps at a moderate applied field cost. The speed is obtained through the use of a very high effective magnetic field, and high resulting precession frequencies. During magnetization reversal, the effective field incorporates a significant exchange field, storing energy in the form of a domain wall surrounding a high magnetic anisotropy nanostructure's region of interest. The exchange field accelerates the reversal and lowers the cost in reversal field. Promising applications to magnetic storage are anticipated.

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Nano-soldering of magnetically aligned three-dimensional nanowire networks

Nanotechnology ◽

10.1088/0957-4484/21/11/115604 ◽

2010 ◽

Vol 21 (11) ◽

pp. 115604 ◽

Cited By ~ 19

Author(s):

Fan Gao ◽

Zhiyong Gu

Keyword(s):

Three Dimensional ◽

Nanowire Networks ◽

Magnetically Aligned

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The Prospect of Three-Dimensional Induction Mapping Inside Magnetic Nanostructures by Combining Electron Holography with Electron Tomography

Microscopy and Microanalysis ◽

10.1017/s1431927604885313 ◽

2004 ◽

Vol 10 (S02) ◽

pp. 1010-1011 ◽

Cited By ~ 6

Author(s):

Rafal E Dunin-Borkowski ◽

Takeshi Kasama

Keyword(s):

Electron Tomography ◽

Three Dimensional ◽

Magnetic Nanostructures ◽

Electron Holography

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

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Three-dimensional modeling of the grain boundary misorientation angle distribution based on two-dimensional experimental texture measurements

Materials Science and Engineering A ◽

10.1016/j.msea.2010.05.037 ◽

2010 ◽

Vol 527 (21-22) ◽

pp. 5604-5612 ◽

Cited By ~ 18

Author(s):

E. Biyikli ◽

D. Canadinc ◽

H.J. Maier ◽

T. Niendorf ◽

S. Top

Keyword(s):

Grain Boundary ◽

Misorientation Angle ◽

Three Dimensional ◽

Angle Distribution ◽

Two Dimensional ◽

Boundary Misorientation ◽

Three Dimensional Modeling ◽

Dimensional Modeling ◽

Grain Boundary Misorientation ◽

Misorientation Angle Distribution

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The Influence of Endwall Contouring on the Performance of a Turbine Nozzle Guide Vane

Volume 1: Turbomachinery ◽

10.1115/98-gt-071 ◽

1998 ◽

Cited By ~ 2

Author(s):

Vincenzo Dossena ◽

Antonio Perdichizzi ◽

Marco Savini

Keyword(s):

Flow Field ◽

Gas Turbine ◽

Guide Vane ◽

Three Dimensional ◽

Angle Distribution ◽

Secondary Effects ◽

Three Dimensional Flow ◽

Nozzle Height ◽

Dimensional Flow ◽

Endwall Contouring

The paper presents the results of a detailed investigation of the flow field in a gas turbine linear cascade. A comparison between a contoured and a planar configuration of the same cascade has been performed, and differences in the three-dimensional flow field are here analyzed and discussed. The flow evolution downstream of the trailing edge was surveyed by means of probe traversing while a 3-D Navier-Stokes solver was employed to obtain information on flow structures inside the vaned passages. The experimental measurements and the numerical simulation of the three-dimensional flow field has been performed for two cascades; one with planar endwalls, and the other with one planar and one profiled endwall, so as to present a reduction of the nozzle height. The investigation was carried out at an isentropic downstream Mach number of 0.6. Airfoils of both cascades were scaled from the same high pressure gas turbine inlet guide vane. Measurements of the three-dimensional flow field have been performed on five planes downstream of the cascades by means of a miniaturized five-hole pressure probe. The presence of endwall contouring strongly influences the secondary effects; the vortex generation and their development is inhibited by the stronger acceleration taking place throughout the cascade. The results show that the secondary effects on the contoured side of the passage are confined in the endwall region, while on the flat side the secondary vortices display characteristics similar to the ones occurring downstream of the planar cascade. The spanwise outlet angle distribution presents a linear variation for most of the nozzle height, with quite low values approaching the contoured endwall. The analysis of mass averaged losses shows a significant performance improvement in the contoured cascade. This has to be ascribed not only to lower secondary losses but also to a reduction of the profile losses.

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Design and Testing of Swept and Leaned Outlet Guide Vanes to Reduce Stator-Strut-Splitter Aerodynamic Flow Interactions

Volume 1: Turbomachinery ◽

10.1115/98-gt-070 ◽

1998 ◽

Cited By ~ 1

Author(s):

A. R. Wadia ◽

P. N. Szucs ◽

K. L. Gundy-Burlet

Keyword(s):

Dimensional Analysis ◽

Test Performance ◽

Potential Flow ◽

Flow Analysis ◽

Three Dimensional ◽

Angle Distribution ◽

Two Dimensional ◽

Guide Vanes ◽

Flow Interactions ◽

Design And Testing

Large circumferential varying pressure levels produced by aerodynamic flow interactions between downstream stators and struts present a potential noise and stability margin liability in a compression component. These interactions are presently controlled by tailoring the camber and/or stagger angles of vanes neighboring the fan frame struts. This paper reports on the design and testing of a unique set of swept and leaned fan outlet guide vanes (OGVs) that do not require this local tailoring even though the OGVs are closely coupled with the fan frame struts and splitter to reduce engine length. The swept and leaned OGVs not only reduce core-duct diffusion, but they also reduce the potential flow interaction between the stator and the strut relative to that produced by conventional radial OGVs. First, the design of the outlet guide vanes using a single bladerow three-dimensional viscous flow analysis is outlined. Next, a two-dimensional potential flow analysis was used for the coupled OGV-frame system to obtain a circumferentially non-uniform stator stagger angle distribution to further reduce the upstream static pressure disturbance. Recognizing the limitations of the two-dimensional potential flow analysis for this highly three-dimensional set of leaned OGVs, as a final evaluation of the OGV-strut system design, a full three-dimensional viscous analysis of a periodic circumferential sector of the OGVs, including the fan frame struts and splitter, was performed. The computer model was derived from a NASA-developed code used in simulating the flow field for external aerodynamic applications with complex geometries. The three-dimensional coupled OGV-frame analysis included the uniformly-staggered OGVs configuration and the variably-staggered OGVs configuration determined by the two-dimensional potential flow analysis. Contrary to the two-dimensional calculations, the three-dimensional analysis revealed significant flow problems with the variably-staggered OGVs configuration and showed less upstream flow non-uniformity with the uniformly-staggered OGVs configuration. The flow redistribution in both the radial and tangential directions, captured fully only in the three-dimensional analysis, was identified as the prime contributor to the lower flow non-uniformity with the uniformly-staggered OGVs configuration. The coupled three-dimensional analysis was also used to validate the design at off-design conditions. Engine test performance and stability measurements with both uniformly- and variably-staggered OGVs configurations with and without the presence of inlet distortion confirmed the conclusions from the three-dimensional analysis.

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