Cargando…

Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles

One fundamental requirement in the search for novel magnetic materials is the possibility of predicting and controlling their magnetic anisotropy and hence the overall hysteretic behavior. We have studied the magnetism of Au:Co films (~30 nm thick) with concentration ratios of 2:1, 1:1, and 1:2, gro...

Descripción completa

Detalles Bibliográficos
Autores principales: Chinni, Federico, Spizzo, Federico, Montoncello, Federico, Mattarello, Valentina, Maurizio, Chiara, Mattei, Giovanni, Del Bianco, Lucia
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5551760/
https://www.ncbi.nlm.nih.gov/pubmed/28773075
http://dx.doi.org/10.3390/ma10070717
_version_ 1783256348380626944
author Chinni, Federico
Spizzo, Federico
Montoncello, Federico
Mattarello, Valentina
Maurizio, Chiara
Mattei, Giovanni
Del Bianco, Lucia
author_facet Chinni, Federico
Spizzo, Federico
Montoncello, Federico
Mattarello, Valentina
Maurizio, Chiara
Mattei, Giovanni
Del Bianco, Lucia
author_sort Chinni, Federico
collection PubMed
description One fundamental requirement in the search for novel magnetic materials is the possibility of predicting and controlling their magnetic anisotropy and hence the overall hysteretic behavior. We have studied the magnetism of Au:Co films (~30 nm thick) with concentration ratios of 2:1, 1:1, and 1:2, grown by magnetron sputtering co-deposition on natively oxidized Si substrates. They consist of a AuCo ferromagnetic alloy in which segregated ultrafine Co particles are dispersed (the fractions of Co in the AuCo alloy and of segregated Co increase with decreasing the Au:Co ratio). We have observed an unexpected hysteretic behavior characterized by in-plane anisotropy and crossed branches in the loops measured along the hard magnetization direction. To elucidate this phenomenon, micromagnetic calculations have been performed for a simplified system composed of two exchange-coupled phases: a AuCo matrix surrounding a Co cluster, which represents an aggregate of particles. The hysteretic features are qualitatively well reproduced provided that the two phases have almost orthogonal anisotropy axes. This requirement can be plausibly fulfilled assuming a dominant magnetoelastic character of the anisotropy in both phases. The achieved conclusions expand the fundamental knowledge on nanocomposite magnetic materials, offering general guidelines for tuning the hysteretic properties of future engineered systems.
format Online
Article
Text
id pubmed-5551760
institution National Center for Biotechnology Information
language English
publishDate 2017
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-55517602017-08-11 Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles Chinni, Federico Spizzo, Federico Montoncello, Federico Mattarello, Valentina Maurizio, Chiara Mattei, Giovanni Del Bianco, Lucia Materials (Basel) Article One fundamental requirement in the search for novel magnetic materials is the possibility of predicting and controlling their magnetic anisotropy and hence the overall hysteretic behavior. We have studied the magnetism of Au:Co films (~30 nm thick) with concentration ratios of 2:1, 1:1, and 1:2, grown by magnetron sputtering co-deposition on natively oxidized Si substrates. They consist of a AuCo ferromagnetic alloy in which segregated ultrafine Co particles are dispersed (the fractions of Co in the AuCo alloy and of segregated Co increase with decreasing the Au:Co ratio). We have observed an unexpected hysteretic behavior characterized by in-plane anisotropy and crossed branches in the loops measured along the hard magnetization direction. To elucidate this phenomenon, micromagnetic calculations have been performed for a simplified system composed of two exchange-coupled phases: a AuCo matrix surrounding a Co cluster, which represents an aggregate of particles. The hysteretic features are qualitatively well reproduced provided that the two phases have almost orthogonal anisotropy axes. This requirement can be plausibly fulfilled assuming a dominant magnetoelastic character of the anisotropy in both phases. The achieved conclusions expand the fundamental knowledge on nanocomposite magnetic materials, offering general guidelines for tuning the hysteretic properties of future engineered systems. MDPI 2017-06-28 /pmc/articles/PMC5551760/ /pubmed/28773075 http://dx.doi.org/10.3390/ma10070717 Text en © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Chinni, Federico
Spizzo, Federico
Montoncello, Federico
Mattarello, Valentina
Maurizio, Chiara
Mattei, Giovanni
Del Bianco, Lucia
Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles
title Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles
title_full Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles
title_fullStr Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles
title_full_unstemmed Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles
title_short Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles
title_sort magnetic hysteresis in nanocomposite films consisting of a ferromagnetic auco alloy and ultrafine co particles
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5551760/
https://www.ncbi.nlm.nih.gov/pubmed/28773075
http://dx.doi.org/10.3390/ma10070717
work_keys_str_mv AT chinnifederico magnetichysteresisinnanocompositefilmsconsistingofaferromagneticaucoalloyandultrafinecoparticles
AT spizzofederico magnetichysteresisinnanocompositefilmsconsistingofaferromagneticaucoalloyandultrafinecoparticles
AT montoncellofederico magnetichysteresisinnanocompositefilmsconsistingofaferromagneticaucoalloyandultrafinecoparticles
AT mattarellovalentina magnetichysteresisinnanocompositefilmsconsistingofaferromagneticaucoalloyandultrafinecoparticles
AT mauriziochiara magnetichysteresisinnanocompositefilmsconsistingofaferromagneticaucoalloyandultrafinecoparticles
AT matteigiovanni magnetichysteresisinnanocompositefilmsconsistingofaferromagneticaucoalloyandultrafinecoparticles
AT delbiancolucia magnetichysteresisinnanocompositefilmsconsistingofaferromagneticaucoalloyandultrafinecoparticles