Diameter‐Controllable Magnetic Properties of Co Nanowire Arrays by Pulsed Electrodeposition

Abstract

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.

Toward uniform electrodeposition of magnetic Co-W mesowires arrays: direct versus pulse current deposition

“…Magnetic metallic wires have received a remarkable interest in the last few years due to their potential applications in devices such as tunable microwave filters [1,2], miniaturized magnetic sensors based on the giant magnetoresistance (GMR) effect [3][4][5] or magnetic recording media with perpendicular-to-plane effective anisotropy [6,7], among others. The implementation of efficient large-scale synthesis methods that allow the mass production of different types of metallic wires in a homogeneous and reproducible manner is essential to cope with the current technological needs in all the aforementioned areas.…”

“…Pulse plating has been satisfactorily used by several authors to fill all the pores of anodic aluminum oxide (AAO) templates with various metal nanowires (e.g., Ni or Co) [11,12]. During the study of Co [4][5][6][7][13][14][15][16][17][18][19][20], Ni [5,16,19,[21][22][23], and their alloys [24][25][26] it was concluded that the quality of the resulting wires strongly depends on the duty cycle. A relatively long pause between the pulses is preferable.…”

“…The wire aspect ratio and the interwire distance have an influence on the magnetic properties since both parameters control the magnetic dipolar interactions in the array [4,6,7,[15][16][17][18]27]. Finally, in order to use nanowires/nanotubes in widespread devices, the materials should not only possess tunable magnetic properties but also acceptable wear and corrosion resistance.…”

Determination of Crystal Growth Geometry Factors and Nucleation Site Densities of Electrodeposited Ferromagnetic Cobalt Nanowire Arrays

“…In the template-assisted method, ferromagnetic metal is electrodeposited into the template with numerous nanochannels with large aspect ratio (cylinder-like nanopores). This method is a very attractive approach to synthesizing ferromagnetic metal nanowires because it can be carried out using simple experimental devices and its cost is low [6]. Typical template materials include ion track-etched polycarbonate films [7-10] and anodic aluminum oxide (AAO) films [11].…”

“…As a result, the diameter (d), length (L) and aspect ratio (L/d) of nanowires, which are electrodeposited into nanochannels, can be adjusted. Therefore, many researchers have synthesized ferromagnetic metal nanowire arrays by using the AAO templates [6,[12][13][14][15][16]. In addition, hexagonal close-packed cobalt (hcp-Co) has large magneto-crystalline anisotropy along the c-axis [17,18].…”