Large area Co nanoring arrays fabricated on silicon substrate by anodic aluminum oxide template-assisted electrodeposition

Abstract

A simple approach based on anodic aluminum oxide template-assisted electrodeposition was developed to fabricate large-area Co nanoring arrays on silicon substrate. The ring outer diameter and interspace can be modulated by varying the anodization parameters. Magnetic measurements and micromagnetic simulation revealed that the onion to vortex (O-V) transition is strongly diameter dependent. With increasing the outer diameter from 100 nm to 300 nm, the O-V switching field gradually changes from positive value to negative value. This was also proved by in situ observation of the magnetic states of the rings under different external fields using magnetic force microscope.

Nanoporous Anodic Aluminum Oxide: Fabrication, Characterization, and Applications

“…Then, electrodeposited metal crystallizes not only at the templates' bottom but also on the walls [126]. With this approach one can obtain uniform metallic nanotubes made from Au [126,127], Co [13,22,66,138], Fe [22,276], Ni [22,264,286], and Pt [66] (Table 3). Here, also the electrochemical methods are majority.…”

“…Metallic nanotubes are useful in applications where high surface electrodes are required, including catalysis (Au [289], Ni [286]) and energy storage (Pd [188]). Also magnetic properties of metallic nanotubes made of Co [13,138], Cd [184,185], and Ni [264] are extensively researched.…”

Synthesis of Single-Crystalline Lead Sulfide Nanoframes and Nanorings

“…These nanorings were studied in terms of electrical and optical properties 11 and possible applications in catalysis, 14 sensors, 8,9 and quantum-mechanical devices. 13 The fabrication of the studied nanoring devices often requires complex, expensive, and time-consuming instrumentation. In contrast, colloidally synthesized nanostructures have the advantage of using simple instrumental setup, low-cost chemicals, scalable syntheses, and effortless processing.…”

“…Beginning with zero-dimensional (0D) nanoparticles of metals and semiconductors of different shapes (e.g., spheres, cubes, octahedrons, stars), it is now also possible to synthesize one-dimensional (1D) nanorods and nanowires of different morphology and two-dimensional (2D) nanoplatelets and nanosheets. , Among these, nanorings are of interest in terms of quantum phenomena to appear when electron or hole wave functions are confined in a toroidal system. A magnetic field induced transition from ground state to chiral state was shown for MBE (molecular beam epitaxy) grown InGaAs nanorings, and theoretical works suggest interesting features of nanorings like Aharanov–Bohm effect. − Metallic nanorings of silver, gold, − nickel, and cobalt were produced by use of lithography techniques involving a template, metal deposition, and argon ion etching. These nanorings were studied in terms of electrical and optical properties and possible applications in catalysis, sensors, , and quantum-mechanical devices .…”

Colloidal lead iodide nanorings

“…They are also highly stable during this process 32. Cobalt or nickel magnetic nanoring arrays may find potential application in magnetic storage devices 30,33,34. Other important examples are gold or silver nanorings with applications in biosensors and InGaAs or GaN semiconductor nanorings in optoelectronical devices 35–38.…”