Magnetic Properties of Electrospun Magnetic Nanofiber Mats after Stabilization and Carbonization.

Nadine Fokin,Andrea Ehrmann,Lilia Sabantina,Andreas Hütten,Marah Trabelsi,Christoph Döpke,Al Mamun,Michaela Klöcker,Tomasz Blachowicz,Timo Grothe

doi:10.3390/ma13071552

Abstract

Magnetic nanofibers are of great interest in basic research, as well as for possible applications in spintronics and neuromorphic computing. Here we report on the preparation of magnetic nanofiber mats by electrospinning polyacrylonitrile (PAN)/nanoparticle solutions, creating a network of arbitrarily oriented nanofibers with a high aspect ratio. Since PAN is a typical precursor for carbon, the magnetic nanofiber mats were stabilized and carbonized after electrospinning. The magnetic properties of nanofiber mats containing magnetite or nickel ferrite nanoparticles were found to depend on the nanoparticle diameters and the potential after-treatment, as compared with raw nanofiber mats. Micromagnetic simulations underlined the different properties of both magnetic materials. Atomic force microscopy and scanning electron microscopy images revealed nearly unchanged morphologies after stabilization without mechanical fixation, which is in strong contrast to pure PAN nanofiber mats. While carbonization at 500 °C left the morphology unaltered, as compared with the stabilized samples, stronger connections between adjacent fibers were formed during carbonization at 800 °C, which may be supportive of magnetic data transmission.

Highlights

Electrospinning makes it possible to create nanofiber mats from diverse materials, such as pure polymers [1,2,3], polymers blends, composite fibers from polymers and ceramics or metals [4,5], and cyclodextrins [6]
The temperature in the chamber was held at 22 ◦ C, while the relative humidity was set to 32%
It should be mentioned that care must be taken in the evaluation of magnetic properties after heating the nanofiber mats above the Curie temperatures of the magnetic

Summary

Introduction

Electrospinning makes it possible to create nanofiber mats from diverse materials, such as pure polymers [1,2,3], polymers blends, composite fibers from polymers and ceramics or metals [4,5], and cyclodextrins [6]. A strong focus of diverse research groups has been related to electrospinning magnetic nanofibers, either as composites [16,17,18] or, after calcination of the composites to remove polymers, as pure metal nanofibers [19,20,21]. Polyacrylonitrile (PAN) can be spun from the low-toxic solvent DMSO [3], making the whole process relatively easy to handle and avoiding unnecessary environmental pollution

Methods

Results

Conclusion