Issue 17, 2013
From the journal:

Nanoscale

Watermelon-like iron nanoparticles: Cr doping effect on magnetism and magnetization interaction reversal

Maninder Kaur,a   Qilin Dai,b   Mark Bowden,c   Mark H. Engelhard,c   Yaqiao Wu,d   Jinke Tangb  and  You Qiang*a  

* Corresponding authors

a Department of Physics, University of Idaho, Moscow, ID 83844, USA
E-mail: youqiang@uidaho.edu

b Department of Physics, University of Wyoming, Laramie, WY 82071, USA

c Pacific Northwest National Laboratory, Richland, WA 99352, USA

d Center for Advanced Energy Studies, Idaho Falls, ID 83401, USA

Abstract

Cr-doped core–shell iron/iron-oxide nanoparticles (NPs) containing 0, 2, 5, and 8 at.% of Cr dopant were synthesized via a nanocluster deposition system and their structural and magnetic properties were investigated. We observed the formation of a σ-FeCr phase in 2 at.% of Cr doping in core–shell NPs. This is unique since it was reported in the past that the σ-phase forms above 20 at.% of Cr. The large coercive field and exchange bias are ascribed to the antiferromagnetic Cr2O3 layer formed with the Fe-oxide shell, which also acts as a passivation layer to decrease the Fe-oxide shell thickness. The additional σ-phase in the core and/or Cr2O3 in the shell cause the hysteresis loop to appear tight waisted near the zero-field axis. The exchange interaction competes with the dipolar interaction with the increase of σ-FeCr grains in the Fe-core. The interaction reversal has been observed in 8 at.% of Cr. The observed reversal mechanism is confirmed from the Henkel plot and delta M value, and is supported by a theoretical watermelon model based on the core–shell nanostructure system.

Graphical abstract: Watermelon-like iron nanoparticles: Cr doping effect on magnetism and magnetization interaction reversal

About
Cited by
Related
Download options Please wait...

Article information

DOI
https://doi.org/10.1039/C3NR02247A
Article type
Paper
Submitted
03 May 2013
Accepted
21 Jun 2013
First published
26 Jun 2013

Nanoscale, 2013,5, 7872-7881

Permissions

Request permissions

Watermelon-like iron nanoparticles: Cr doping effect on magnetism and magnetization interaction reversal

M. Kaur, Q. Dai, M. Bowden, M. H. Engelhard, Y. Wu, J. Tang and Y. Qiang, Nanoscale, 2013, 5, 7872 DOI: 10.1039/C3NR02247A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements