Effective macrospin model for $Co_{x}Fe_{3-x}O_{4}$ nanoparticle: decreasing the anisotropy by Co-doping?

David Serantes; Daniel Faílde; Daniel Baldomir; Beatriz Pelaz; Pablo del Pino; Roy W. Chantrell

Effective macrospin model for $Co_{x}Fe_{3-x}O_{4}$ nanoparticle: decreasing the anisotropy by Co-doping?

David Serantes, Daniel Faílde, Daniel Baldomir, Beatriz Pelaz, Pablo del Pino, Roy W. Chantrell

Physics

Research output: Working paper › Preprint

Abstract

$Co$-doping of $Fe_{3}O_{4}$ magnetic nanoparticles is an effective way to tailor their magnetic properties. When considering the two extreme cases of the $Co_{x}Fe_{3-x}O_{4}$ series, i.e. the $x=0$ and $x=1$ values, one finds that the system evolves from a negative cubic-anisotropy energy constant, $K_{C}^{-}0$. Thus, what happens for intermediate $x$-compositions? In this work we present a very simple phenomenological model for the anisotropy, under the \textit{macrospin} approximation, in which the resultant anisotropy is just directly proportional to the amount of $Co$. First, we perform a detailed analysis on a rather ideal system in which the extreme values have the same magnitude (i.e. $|K_{C}^{-}|=|K_{C}^{+}|$) and then we focus on the real $Co_{x}Fe_{3-x}O_{4}$ system, for which $|K_{C}^{+}|\sim 18|K_{C}^{-}|$. Remarkably, the approach reproduces rather well the experimental values of the heating performance of $Co_{x}Fe_{3-x}O_{4}$ nanoparticles, suggesting that our simple approach may in fact be a good representation of the real situation. This gives rise to an intriguing related possibility arises: a $Co$-doping composition should exist for which the effective anisotropy tends to zero, estimated here as 0.05.

Original language	English
Publication status	Published - 23 Sept 2019

Publication series

Name	arXiv

Bibliographical note

6 pages, 7 figures

Keywords

cond-mat.mtrl-sci
cond-mat.mes-hall

Access to Document

arxiv-preprint-1909.10643v1Accepted author manuscript, 1.15 MB
1909.10643v1

https://arxiv.org/abs/1909.10643

Cite this

@techreport{9533415dd75045d3b490c9a16597f884,

title = "Effective macrospin model for $Co_{x}Fe_{3-x}O_{4}$ nanoparticle: decreasing the anisotropy by Co-doping?",

abstract = " $Co$-doping of $Fe_{3}O_{4}$ magnetic nanoparticles is an effective way to tailor their magnetic properties. When considering the two extreme cases of the $Co_{x}Fe_{3-x}O_{4}$ series, i.e. the $x=0$ and $x=1$ values, one finds that the system evolves from a negative cubic-anisotropy energy constant, $K_{C}^{-}0$. Thus, what happens for intermediate $x$-compositions? In this work we present a very simple phenomenological model for the anisotropy, under the \textit{macrospin} approximation, in which the resultant anisotropy is just directly proportional to the amount of $Co$. First, we perform a detailed analysis on a rather ideal system in which the extreme values have the same magnitude (i.e. $|K_{C}^{-}|=|K_{C}^{+}|$) and then we focus on the real $Co_{x}Fe_{3-x}O_{4}$ system, for which $|K_{C}^{+}|\sim 18|K_{C}^{-}|$. Remarkably, the approach reproduces rather well the experimental values of the heating performance of $Co_{x}Fe_{3-x}O_{4}$ nanoparticles, suggesting that our simple approach may in fact be a good representation of the real situation. This gives rise to an intriguing related possibility arises: a $Co$-doping composition should exist for which the effective anisotropy tends to zero, estimated here as 0.05. ",

keywords = "cond-mat.mtrl-sci, cond-mat.mes-hall",

author = "David Serantes and Daniel Fa{\'i}lde and Daniel Baldomir and Beatriz Pelaz and Pino, {Pablo del} and Chantrell, {Roy W.}",

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T2 - decreasing the anisotropy by Co-doping?

AU - Serantes, David

AU - Faílde, Daniel

AU - Baldomir, Daniel

AU - Pelaz, Beatriz

AU - Pino, Pablo del

AU - Chantrell, Roy W.

N1 - 6 pages, 7 figures

PY - 2019/9/23

Y1 - 2019/9/23

N2 - $Co$-doping of $Fe_{3}O_{4}$ magnetic nanoparticles is an effective way to tailor their magnetic properties. When considering the two extreme cases of the $Co_{x}Fe_{3-x}O_{4}$ series, i.e. the $x=0$ and $x=1$ values, one finds that the system evolves from a negative cubic-anisotropy energy constant, $K_{C}^{-}0$. Thus, what happens for intermediate $x$-compositions? In this work we present a very simple phenomenological model for the anisotropy, under the \textit{macrospin} approximation, in which the resultant anisotropy is just directly proportional to the amount of $Co$. First, we perform a detailed analysis on a rather ideal system in which the extreme values have the same magnitude (i.e. $|K_{C}^{-}|=|K_{C}^{+}|$) and then we focus on the real $Co_{x}Fe_{3-x}O_{4}$ system, for which $|K_{C}^{+}|\sim 18|K_{C}^{-}|$. Remarkably, the approach reproduces rather well the experimental values of the heating performance of $Co_{x}Fe_{3-x}O_{4}$ nanoparticles, suggesting that our simple approach may in fact be a good representation of the real situation. This gives rise to an intriguing related possibility arises: a $Co$-doping composition should exist for which the effective anisotropy tends to zero, estimated here as 0.05.

AB - $Co$-doping of $Fe_{3}O_{4}$ magnetic nanoparticles is an effective way to tailor their magnetic properties. When considering the two extreme cases of the $Co_{x}Fe_{3-x}O_{4}$ series, i.e. the $x=0$ and $x=1$ values, one finds that the system evolves from a negative cubic-anisotropy energy constant, $K_{C}^{-}0$. Thus, what happens for intermediate $x$-compositions? In this work we present a very simple phenomenological model for the anisotropy, under the \textit{macrospin} approximation, in which the resultant anisotropy is just directly proportional to the amount of $Co$. First, we perform a detailed analysis on a rather ideal system in which the extreme values have the same magnitude (i.e. $|K_{C}^{-}|=|K_{C}^{+}|$) and then we focus on the real $Co_{x}Fe_{3-x}O_{4}$ system, for which $|K_{C}^{+}|\sim 18|K_{C}^{-}|$. Remarkably, the approach reproduces rather well the experimental values of the heating performance of $Co_{x}Fe_{3-x}O_{4}$ nanoparticles, suggesting that our simple approach may in fact be a good representation of the real situation. This gives rise to an intriguing related possibility arises: a $Co$-doping composition should exist for which the effective anisotropy tends to zero, estimated here as 0.05.

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KW - cond-mat.mes-hall

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BT - Effective macrospin model for $Co_{x}Fe_{3-x}O_{4}$ nanoparticle

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