Superspin ensembles of oxidized- Co xFe 1-xS 2 with embedded magnetic nanoparticles

Henrik Gabold; Chinawat Ekwongsa; Pinit Kidkhunthod; Rattikorn Yimnirun; Matthias Opel; Amitesh Paul

doi:10.1557/s43578-022-00871-0

Superspin ensembles of oxidized- Co xFe 1-xS 2 with embedded magnetic nanoparticles

Henrik Gabold, Chinawat Ekwongsa, Pinit Kidkhunthod, Rattikorn Yimnirun, Matthias Opel, Amitesh Paul^*

^*Corresponding author for this work

Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

Abstract

We report on the magnetic behavior of oxidized-Co_xFe₁_-_xS₂ nanocrystals as they assemble to form nanoparticles. The morphologies show a typical NP size of around 250–100 nm and NC sizes of around 7 nm. Using extended absorption fine structure, we confirm the existence of Co-oxides for x≥ 0.5. The temperature dependence of DC magnetization and AC susceptibility reveals a number of magnetic phases in these NP oxides. Co-existence of blocking and freezing behaviors via intercluster dipolar interactions is found consistent with the antiferromagnetic exchange interactions within clusters embedded within a “supermagnetic” ensemble. The Fe substitution influences the supermagnetism of the ensemble, while the AF behavior of the embedded clusters remains largely unaffected. The overall behavior can be described by a phase diagram which can be understood in terms of competition between the various dipolar, inter-, and intracluster interactions within the random magnetic anisotropy model. Graphical abstract: [Figure not available: see fulltext.].

Original language	English
Journal	Journal of Materials Research
DOIs	https://doi.org/10.1557/s43578-022-00871-0 https://doi.org/10.1557/s43578-022-00871-0
State	Published - 9 Jan 2023

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@article{74ea502fb4d44962b1b0a0893ea81928,

title = "Superspin ensembles of oxidized- Co xFe 1-xS 2 with embedded magnetic nanoparticles",

abstract = "We report on the magnetic behavior of oxidized-CoxFe1-xS2 nanocrystals as they assemble to form nanoparticles. The morphologies show a typical NP size of around 250–100 nm and NC sizes of around 7 nm. Using extended absorption fine structure, we confirm the existence of Co-oxides for x≥ 0.5. The temperature dependence of DC magnetization and AC susceptibility reveals a number of magnetic phases in these NP oxides. Co-existence of blocking and freezing behaviors via intercluster dipolar interactions is found consistent with the antiferromagnetic exchange interactions within clusters embedded within a “supermagnetic” ensemble. The Fe substitution influences the supermagnetism of the ensemble, while the AF behavior of the embedded clusters remains largely unaffected. The overall behavior can be described by a phase diagram which can be understood in terms of competition between the various dipolar, inter-, and intracluster interactions within the random magnetic anisotropy model. Graphical abstract: [Figure not available: see fulltext.].",

author = "Henrik Gabold and Chinawat Ekwongsa and Pinit Kidkhunthod and Rattikorn Yimnirun and Matthias Opel and Amitesh Paul",

note = "Publisher Copyright: {\textcopyright} 2023, The Author(s), under exclusive licence to The Materials Research Society.",

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month = jan,

day = "9",

doi = "10.1557/s43578-022-00871-0",

language = "英语",

journal = "Journal of Materials Research",

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T1 - Superspin ensembles of oxidized- Co xFe 1-xS 2 with embedded magnetic nanoparticles

AU - Gabold, Henrik

AU - Ekwongsa, Chinawat

AU - Kidkhunthod, Pinit

AU - Yimnirun, Rattikorn

AU - Opel, Matthias

AU - Paul, Amitesh

PY - 2023/1/9

Y1 - 2023/1/9

N2 - We report on the magnetic behavior of oxidized-CoxFe1-xS2 nanocrystals as they assemble to form nanoparticles. The morphologies show a typical NP size of around 250–100 nm and NC sizes of around 7 nm. Using extended absorption fine structure, we confirm the existence of Co-oxides for x≥ 0.5. The temperature dependence of DC magnetization and AC susceptibility reveals a number of magnetic phases in these NP oxides. Co-existence of blocking and freezing behaviors via intercluster dipolar interactions is found consistent with the antiferromagnetic exchange interactions within clusters embedded within a “supermagnetic” ensemble. The Fe substitution influences the supermagnetism of the ensemble, while the AF behavior of the embedded clusters remains largely unaffected. The overall behavior can be described by a phase diagram which can be understood in terms of competition between the various dipolar, inter-, and intracluster interactions within the random magnetic anisotropy model. Graphical abstract: [Figure not available: see fulltext.].

AB - We report on the magnetic behavior of oxidized-CoxFe1-xS2 nanocrystals as they assemble to form nanoparticles. The morphologies show a typical NP size of around 250–100 nm and NC sizes of around 7 nm. Using extended absorption fine structure, we confirm the existence of Co-oxides for x≥ 0.5. The temperature dependence of DC magnetization and AC susceptibility reveals a number of magnetic phases in these NP oxides. Co-existence of blocking and freezing behaviors via intercluster dipolar interactions is found consistent with the antiferromagnetic exchange interactions within clusters embedded within a “supermagnetic” ensemble. The Fe substitution influences the supermagnetism of the ensemble, while the AF behavior of the embedded clusters remains largely unaffected. The overall behavior can be described by a phase diagram which can be understood in terms of competition between the various dipolar, inter-, and intracluster interactions within the random magnetic anisotropy model. Graphical abstract: [Figure not available: see fulltext.].

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U2 - 10.1557/s43578-022-00871-0

DO - 10.1557/s43578-022-00871-0

M3 - 文章

SN - 0884-2914

JO - Journal of Materials Research

JF - Journal of Materials Research

ER -

Superspin ensembles of oxidized- Co xFe 1-xS 2 with embedded magnetic nanoparticles

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