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

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1133
Author(s):  
Nicolas Marchal ◽  
Tristan da Câmara Santa Clara Gomes ◽  
Flavio Abreu Araujo ◽  
Luc Piraux

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.

2011 ◽  
Vol 1350 ◽  
Author(s):  
Andrew J. Lohn ◽  
Jin-Woo Han ◽  
Nobuhiko P. Kobayashi

ABSTRACTSurface photovoltage of three-dimensional networks composed of fused indium phosphide (InP) nanowires is discussed. Particular emphasis is given to the dependence of surface photovoltage on the chopping frequency of light that excites the nanowire network as observed in regions which are laterally separated from the excitation. The nanowire network is modeled as a thin film to simplify numerical solutions to transport equations which aids in the interpretation of diffusion and drift of photo-generated carriers within the nanowire network.


Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 693 ◽  
Author(s):  
Liana Movsesyan ◽  
Albert Maijenburg ◽  
Noel Goethals ◽  
Wilfried Sigle ◽  
Anne Spende ◽  
...  

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.


Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 221
Author(s):  
Tristan da Câmara Santa Clara Gomes ◽  
Nicolas Marchal ◽  
Flavio Abreu Araujo ◽  
Yenni Velázquez Galván ◽  
Joaquín de la Torre Medina ◽  
...  

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.


Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 986
Author(s):  
Michael Rudolf Koblischka ◽  
Anjela Koblischka-Veneva ◽  
XianLin Zeng ◽  
Essia Hannachi ◽  
Yassine Slimani

Resistance measurements were performed on Bi2Sr2CaCu2O8+δ (Bi-2212) fabric-like nanowire networks or nanofiber mats in the temperature interval 3 K ≤T≤ 300 K. The nanowire fabrics were prepared by means of electrospinning, and consist of long (up to 100 μm) individual nanowires with a mean diameter of 250 nm. The microstructure of the nanowire network fiber mats and of the individual nanowires was thoroughly characterized by electron microscopy showing that the nanowires can be as thin as a single Bi-2212 grain. The polycrystalline nanowires are found to have a texture in the direction of the original polymer nanowire. The overall structure of the nanofiber mats is characterized by numerous interconnects among the nanowires, which enable current flow across the whole sample. The fluctuation-induced conductivity (excess conductivity) above the superconducting transition temperature, Tc, was analyzed using the Aslamzov-Larkin model. Four distinct fluctuation regimes (short-wave, two-dimensional, three-dimensional and critical fluctuation regimes) could be identified in the Bi-2212 nanowire fabric samples. These regimes in such nanowire network samples are discussed in detail for the first time. Based on this analysis, we determine several superconducting parameters from the resistance data.


2021 ◽  
Vol 21 ◽  
Author(s):  
Madhukar Garg ◽  
Anju Goyal ◽  
Sapna Kumari

: Cubosomes are highly stable nanostructured liquid crystalline dosage delivery form derived from amphiphilic lipids and polymer-based stabilizers converting it in a form of effective biocompatible carrier for the drug delivery. The delivery form comprised of bicontinuous lipid bilayers arranged in three dimensional honeycombs like structure provided with two internal aqueous channels for incorporation of number of biologically active ingredients. In contrast liposomes they provide large surface area for incorporation of different types of ingredients. Due to the distinct advantages of biocompatibility and thermodynamic stability, cubosomes have remained the first preference as method of choice in the sustained release, controlled release and targeted release dosage forms as new drug delivery system for the better release of the drugs. As lot of advancement in the new form of dosage form has bring the novel avenues in drug delivery mechanisms so it was matter of worth to compile the latest updates on the various aspects of mentioned therapeutic delivery system including its structure, routes of applications along with the potential applications to encapsulate variety drugs to serve health related benefits.


Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1809
Author(s):  
Zhanzhi Liu ◽  
Ying Li ◽  
Jing Wu ◽  
Sheng Chen

d-mannose has exhibited excellent physiological properties in the food, pharmaceutical, and feed industries. Therefore, emerging attention has been applied to enzymatic production of d-mannose due to its advantage over chemical synthesis. The gene age of N-acetyl-d-glucosamine 2-epimerase family epimerase/isomerase (AGEase) derived from Pseudomonas geniculata was amplified, and the recombinant P. geniculata AGEase was characterized. The optimal temperature and pH of P. geniculata AGEase were 60 °C and 7.5, respectively. The Km, kcat, and kcat/Km of P. geniculata AGEase for d-mannose were 49.2 ± 8.5 mM, 476.3 ± 4.0 s−1, and 9.7 ± 0.5 s−1·mM−1, respectively. The recombinant P. geniculata AGEase was classified into the YihS enzyme subfamily in the AGE enzyme family by analyzing its substrate specificity and active center of the three-dimensional (3D) structure. Further studies on the kinetics of different substrates showed that the P. geniculata AGEase belongs to the d-mannose isomerase of the YihS enzyme. The P. geniculata AGEase catalyzed the synthesis of d-mannose with d-fructose as a substrate, and the conversion rate was as high as 39.3% with the d-mannose yield of 78.6 g·L−1 under optimal reaction conditions of 200 g·L−1d-fructose and 2.5 U·mL−1P. geniculata AGEase. This novel P. geniculata AGEase has potential applications in the industrial production of d-mannose.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Muhammad Naqi ◽  
Kyung Hwan Choi ◽  
Hocheon Yoo ◽  
Sudong Chae ◽  
Bum Jun Kim ◽  
...  

AbstractLow-temperature-processed semiconductors are an emerging need for next-generation scalable electronics, and these semiconductors need to feature large-area fabrication, solution processability, high electrical performance, and wide spectral optical absorption properties. Although various strategies of low-temperature-processed n-type semiconductors have been achieved, the development of high-performance p-type semiconductors at low temperature is still limited. Here, we report a unique low-temperature-processed method to synthesize tellurium nanowire networks (Te-nanonets) over a scalable area for the fabrication of high-performance large-area p-type field-effect transistors (FETs) with uniform and stable electrical and optical properties. Maximum mobility of 4.7 cm2/Vs, an on/off current ratio of 1 × 104, and a maximum transconductance of 2.18 µS are achieved. To further demonstrate the applicability of the proposed semiconductor, the electrical performance of a Te-nanonet-based transistor array of 42 devices is also measured, revealing stable and uniform results. Finally, to broaden the applicability of p-type Te-nanonet-based FETs, optical measurements are demonstrated over a wide spectral range, revealing an exceptionally uniform optical performance.


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