Plasma-assisted synthesis and high-resolution characterization of anisotropic elemental and bimetallic core-shell magnetic nanoparticles.

M Hennes,A Lotnyk,S G Mayr

doi:10.3762/bjnano.5.54

Abstract

Magnetically anisotropic as well as magnetic core–shell nanoparticles (CS-NPs) with controllable properties are highly desirable in a broad range of applications. With this background, a setup for the synthesis of heterostructured magnetic core–shell nanoparticles, which relies on (optionally pulsed) DC plasma gas condensation has been developed. We demonstrate the synthesis of elemental nickel nanoparticles with highly tunable sizes and shapes and Ni@Cu CS-NPs with an average shell thickness of 10 nm as determined with scanning electron microscopy, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy measurements. An analytical model that relies on classical kinetic gas theory is used to describe the deposition of Cu shell atoms on top of existing Ni cores. Its predictive power and possible implications for the growth of heterostructured NP in gas condensation processes are discussed.

Highlights

Due to their size, novel physical properties and the possibility of contactless manipulation, magnetic nanoparticles can be employed as powerful nanotools in many areas of biology, biophysics and medicine [1]
We observed that crossing a minimum value of x, the particle flow ceased abruptly. This has been reported in earlier studies [13], but the origin of this effect remains unclear to date
We set up a plasma gas-condensation apparatus for the synthesis of nanoparticles and demonstrated the successful production of highly tunable elemental and CS-structured magnetic nanoparticles

Summary

Introduction

Novel physical properties and the possibility of contactless manipulation, magnetic nanoparticles can be employed as powerful nanotools in many areas of biology, biophysics and medicine [1]. Possible applications include their use as contrast agents for cell tracking via magnetic resonance imaging (MRI) [2], as colloidal mediators in cancer therapy (hyperthermia) [3] or as nanocarriers for targeted drug delivery [4]. The synthesis of well designed nanoalloys [5], combining two and more metals at the nanoscale, might circumvent this problem.

Results

Discussion

Conclusion