scholarly journals Control of the asymmetric growth of nanowire arrays with gradient profiles

RSC Advances ◽  
2021 ◽  
Vol 11 (42) ◽  
pp. 25892-25900
Author(s):  
Juan Patiño Cárdenas ◽  
Armando Encinas ◽  
Rossana Ramírez Villegas ◽  
Joaquín de la Torre Medina
Keyword(s):  
Nanowire Arrays ◽  
Non Linear ◽  
Asymmetric Growth ◽  
Co Nanowires

A novel electrochemical methodology for the growth of arrays of Ni and Co nanowires (NWs) with linear and non-linear varying micro-height gradient profiles (μHGPs), has been developed.

Magnetic Properties of Uniform Nanowire arrays

1996 ◽  
Vol 431 ◽  
Author(s):  
P. P. Nguyen ◽  
R. J. Tonucci
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Thermal Activation ◽  
Magnetic Measurements ◽  
Nanowire Arrays ◽  
Activation Model ◽  
Co Nanowires

AbstractFabrication and magnetic measurements of ferromagnetic (Ni and Co) nanowire arrays using nanochannel glass templates are presented. These nanowire arrays have novel characteristics: The nanowires are very parallel (to within a fraction of a degree) and regularly placed. They are circular with extremely uniform diameter (of less than 80 nm for some samples) both along individual wire's length and among different wires within an array. Magnetic measurements show enhanced coercivities compared to the bulk values. The saturation magnetization for Ni nanowires depends much more strongly on temperature than that for Co nanowires. The coercivities are also dependent strongly on temperature and can be explained by a thermal-activation model.

scholarly journals Diameter-Controllable Magnetic Properties of Co Nanowire Arrays by Pulsed Electrodeposition

2010 ◽  
Vol 2010 ◽  
pp. 1-4 ◽  
Author(s):  
Youwen Yang ◽  
Yanbiao Chen ◽  
Yucheng Wu ◽  
Xiangying Chen ◽  
Mingguang Kong
Keyword(s):  
Magnetic Properties ◽  
Crystal Structures ◽  
Magnetization Reversal ◽  
Nanowire Arrays ◽  
Cylindrical Shape ◽  
Perpendicular Anisotropy ◽  
Alumina Membranes ◽  
Pulsed Electrodeposition ◽  
Different Diameters ◽  
Co Nanowires

The Co nanowires with different diameters were prepared by pulsed electrodeposition into anodic alumina membranes oxide templates. The micrographs and crystal structures of nanowires were studied by FE-SEM, TEM, and XRD. Due to their cylindrical shape, the nanowires exhibit perpendicular anisotropy. The coercivity and loop squareness (Mr/Ms) of Co nanowires depend strongly on the diameter. Both coercivity and Mr/Ms decrease with increasing wire diameter. The behavior of the nanowires is explained briefly in terms of localized magnetization reversal.

CROSSOVER BETWEEN MAGNETIC REVERSAL MODES IN ORDERED Ni AND Co NANOTUBE ARRAYS

SPIN ◽  
2012 ◽  
Vol 02 (04) ◽  
pp. 1250014 ◽  
Author(s):  
MARIANA P. PROENCA ◽  
CELIA T. SOUSA ◽  
JOAO VENTURA ◽  
JOAO P. ARAUJO ◽  
JUAN ESCRIG ◽  
...  
Keyword(s):  
Domain Wall ◽  
Critical Diameter ◽  
Theoretical Data ◽  
Nanowire Arrays ◽  
Nanotube Arrays ◽  
Simple Analytical Model ◽  
Magnetic Reversal ◽  
Ordered Arrays ◽  
Nanoporous Alumina Templates ◽  
Co Nanowires

Ordered arrays of Ni and Co nanowires and nanotubes, with diameters between 30 nm and 60 nm, were prepared by electrodeposition into nanoporous alumina templates. The study of the corresponding magnetization reversal processes was performed by analyzing the angular dependence of coercivity (Hc) and using a simple analytical model. The agreement between experimental and theoretical data shows that magnetization in nanowire arrays reverses by means of nucleation and propagation of a transverse domain wall, independently of the diameter. However, a critical diameter of ~ 50 nm was found in the case of nanotubes, above which a nonmonotonic angular dependent Hc was observed, evidencing a transition between vortex and transverse reversal modes.

Nanowire Arrays with Specialized Geometries for Magnetoelectronics (Invited)

2004 ◽  
Vol 853 ◽  
Author(s):  
Bethanie J. H. Stadler ◽  
Na hyoung Kim ◽  
Liwen Tan ◽  
Jia Zou ◽  
Kate Kelchner ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Pore Diameter ◽  
Sensor Arrays ◽  
Nanowire Arrays ◽  
Magnetic Nanowires ◽  
Magnetic Field Sensors ◽  
Magnetoresistive Sensor ◽  
Multilayered Nanowires ◽  
Co Nanowires

This work focuses on the fabrication of magnetic nanowires with specialized geometries, such as Y-junctions, tapers and multilayers, for magnetoresistive sensor arrays. First, anodic alumina nanopores were grown with diameters of 20–250nm and lengths up to tens of microns. These pores were removed from their Al substrates and the barrier oxide was removed. Co nanowires were initially grown inside the pores by electrochemical deposition. It was shown that the coercivity and remnant magnetization could be tripled in (100)-oriented Co by shrinking the pore diameter/interpore spacing from 150/300nm to 40/80nm. These properties were further enhanced by fabricating (002)-oriented Co using the proper pH and applying a magnetic field during growth. The ability to connect two or more nanostructures is critical to the long term success of nanoelectronics and circuits. Here, Y-junctions were grown by subsequent growth of 40nm then 20nm pores such that two smaller pores extended from the bottom of each larger pore. These pores were then filled with Co in order to produce Y-junctions in the magnetic nanowires. Next, multilayered nanowires were fabricated with alternating layers of Cu and Co. The Co layer thickness was varied in order to study the affect of shape anisotropy on the magnetic properties of Co layers inside arrays. Finally, several configurations for magnetoresistive magnetic field sensors were described.

Epitaxy-driven vertical growth of single-crystalline cobalt nanowire arrays by chemical vapor deposition

2015 ◽  
Vol 3 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Si-in Kim ◽  
Hana Yoon ◽  
Hyoban Lee ◽  
Sunghun Lee ◽  
Younghun Jo ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Nanowire Arrays ◽  
Chemical Vapor Deposition Method ◽  
Deposition Method ◽  
Vertical Orientation ◽  
Single Crystalline ◽  
Sapphire Substrates ◽  
Co Nanowires

Ferromagnetic single-crystalline Co nanowires (NWs) aligned in a vertical orientation are epitaxially grown on m-cut sapphire substrates by a rapid and versatile chemical vapor deposition method. They were transformed into Co3O4 nanotubes by thermal annealing under dilute O2 conditions.

scholarly journals ANGULAR DEPENDENCE OF MAGNETIC PROPERTIES IN Co NANOWIRE ARRAYS

2018 ◽  
Vol 56 (1A) ◽  
pp. 65
Author(s):  
Luu Van Thiem
Keyword(s):  
Magnetic Properties ◽  
Angular Dependence ◽  
Room Temperature ◽  
Average Length ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
Crystallographic Structure ◽  
Sem Image ◽  
Co Nanowires

The Co nanowire arrays were fabricated by electrodeposition method by using the porous polycarbonate template. Study on crystallographic structure, micro structure, and the element composition confirmed the quality of the fabricated Co nanowires. SEM image shows the wires with an average diameter of 200 nm and the average length of 9 mm. The magnetic properties, measured at room temperature using vibrating sample magnetometry (VSM), displays that the nanowires have anisotropic property. The angular dependence of coercivity of Co nanowires has been studied. The decrease of the coercivity, when the angular changed from 0 o to 90 o, will be discussed. 

B. The Non-Linear Calculations for Pulsating Stars

1967 ◽  
Vol 28 ◽  
pp. 105-176
Author(s):  
Robert F. Christy
Keyword(s):  
Major Part ◽  
Afternoon Session ◽  
Discussion Session ◽  
Pulsating Stars ◽  
Fourth Symposium ◽  
Non Linear ◽  
Considerable Discussion ◽  
Informal Approach ◽  
Preceding Session

(Ed. note: The custom in these Symposia has been to have a summary-introductory presentation which lasts about 1 to 1.5 hours, during which discussion from the floor is minor and usually directed at technical clarification. The remainder of the session is then devoted to discussion of the whole subject, oriented around the summary-introduction. The preceding session, I-A, at Nice, followed this pattern. Christy suggested that we might experiment in his presentation with a much more informal approach, allowing considerable discussion of the points raised in the summary-introduction during its presentation, with perhaps the entire morning spent in this way, reserving the afternoon session for discussion only. At Varenna, in the Fourth Symposium, several of the summaryintroductory papers presented from the astronomical viewpoint had been so full of concepts unfamiliar to a number of the aerodynamicists-physicists present, that a major part of the following discussion session had been devoted to simply clarifying concepts and then repeating a considerable amount of what had been summarized. So, always looking for alternatives which help to increase the understanding between the different disciplines by introducing clarification of concept as expeditiously as possible, we tried Christy's suggestion. Thus you will find the pattern of the following different from that in session I-A. I am much indebted to Christy for extensive collaboration in editing the resulting combined presentation and discussion. As always, however, I have taken upon myself the responsibility for the final editing, and so all shortcomings are on my head.)

A decomposition method in non-linear programmm

Optimization ◽  
1975 ◽  
Vol 6 (4) ◽  
pp. 549-559
Author(s):  
L. Gerencsér
Keyword(s):  
Decomposition Method ◽  
Non Linear
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