Magnetic force microscopy study of the switching field distribution of low density arrays of single domain magnetic nanowires

TL;DR

This study uses magnetic force microscopy to analyze the switching field distribution in low-density arrays of ferromagnetic nanowires, revealing narrower distributions than high-density arrays and examining effects of diameter and composition.

Contribution

It provides in situ MFM measurements of magnetization reversal in low-density nanowire arrays, highlighting differences from high-density arrays and analyzing factors affecting SFD.

Findings

Narrower switching field distributions compared to high-density arrays.

Weak broadening of magnetization curves attributed to intrinsic SFD.

Diameter and composition influence on the switching behavior.

Abstract

In the present work, we report on the in situ magnetic force microscopy (MFM) study of the magnetization reversal in two-dimensional arrays of ferromagnetic Ni80Fe20 and Co55Fe45 nanowires(NW) with different diameters (40, 50, 70 and 100 nm) deposited inside low porosity (P<1%) nanoporous polycarbonate membranes. In such arrays, the nanowires are sufficiently isolated from each other so that long range dipolar interactions can be neglected. The MFM experiments performed for different magnetization states at the same spot of the samples are analysed to determine the switching field distribution (SFD). The magnetization curves obtained from the MFM images are relatively square shaped. The SFD widths are narrower compared to those obtained for high density arrays. The weak broadening of the curves may be ascribed to the NW intrinsic SFD. The influence of diameter and composition of the ferromagnetic NW is also investigated.