Preparation and physical properties of soft magnetic nickel-cobalt nanowires with modulated diameters

TL;DR

This paper presents a versatile method for fabricating multisegmented magnetic nanowires with controlled diameters and lengths, along with an analytical model to analyze their magnetic properties.

Contribution

It introduces a novel fabrication process for multisegmented magnetic nanowires and an analytical model to predict their magnetic switching behavior without adjustable parameters.

Findings

Successful fabrication of multisegmented nanowires with controlled dimensions

Analytical model accurately predicts magnetization loops and switching fields

Model considers inter-wire interactions and end-domain effects

Abstract

We establish a method to produce cylindrical magnetic nanowires displaying several segments, with a large versatility in terms of segment diameter and length. It is based on electroplating in alumina templates, the latter being prepared by several steps of anodization, wet etching and atomic layer deposition to produce, widen or shrink pores, respectively. We propose an analytical model to analyze the in-plane and out-of-plane magnetization loops of dense assemblies of multisegmented wires. The model considers inter-wires dipolar fields, end-domain curling and predicts the switching field of individual wires with no adjustable parameter. Its ingredients are crucial to extract reliable parameters from the fitting of loops, such as magnetization or the porosity of the array.