Magnetic Properties of the Densely Packed Ultra-Long Ni Nanowires Encapsulated in Alumina Membrane

Abstract

High-quality and compact arrays of Ni nanowires with a high ratio (up to 700) were obtained by DC electrochemical deposition into porous anodic alumina membranes with a distance between pores equal to 105 nm. The nanowire arrays were examined using scanning electron microscopy, X-ray diffraction analysis and vibration magnetometry at 300 K and 4.2 K. Microscopic and X-ray diffraction results showed that Ni nanowires are homogeneous, with smooth walls and mostly single-crystalline materials with a 220-oriented growth direction. The magnetic properties of the samples (coercivity and squareness) depend more on the length of the nanowires and the packing factor (the volume fraction of the nanowires in the membrane). It is shown that the dipolar interaction changes the demagnetizing field during a reversal magnetization of the Ni nanowires, and the general effective field of magnetostatic uniaxial shape anisotropy. The effect of magnetostatic interaction between ultra-long nanowires (with an aspect ratio of >500) in samples with a packing factor of ≥37% leads to a reversal magnetization state, in which a “curling”-type model of nanowire behavior is realized.

Electrochemical Synthesis of Zinc Oxide Nanostructures on Flexible Substrate and Application as an Electrochemical Immunoglobulin-G Immunosensor

“…The ability to obtain ZnO in nanostructured form is extremely interesting because nanostructured morphology allows electrodes with higher surface area and thus higher reactivity to be fabricated [47]. These properties are of great importance in many applications, especially for batteries [48,49], electrolyzes [50][51][52], solar cells [53,54], magnetic devices [55,56] and sensors [57][58][59]. In this work we explored the possibility of using electrochemically obtained ZnO nanorods (ZnO-NRs) as a basis for the fabrication of immunosensors for human immunoglobulin G (H-IgG).…”

The Interrelation of Synthesis Conditions and Wettability Properties of the Porous Anodic Alumina Membranes

“…Therefore, the pore walls of the oxide cells are simultaneously etched (chemical pore widening), that is, the pore diameter changes (increases). The PAA membrane production is described in more detail in [ 52 ].…”

Electrodeposition conditions-dependent crystal structure, morphology and electronic properties of Bi films

“…In contradiction, as-deposited samples are characterized by a temperature-independent scattering and weaker temperature dependence of mobility at low temperatures. Their more complicated temperature dependence of resistivity is a combination of comparable contributions of mobility and concentration dependences [63,64].…”