Exchange bias in Co nanoparticles embedded in an Mn matrix

Neus Domingo; Alberto M. Testa; Dino Fiorani; Chris Binns; Stephen Baker; Javier Tejada

doi:10.1016/j.jmmm.2007.02.058

Exchange bias in Co nanoparticles embedded in an Mn matrix

Neus Domingo, Alberto M. Testa, Dino Fiorani, Chris Binns, Stephen Baker, Javier Tejada

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

35 Scopus citations

Abstract

Magnetic properties of Co nanoparticles of 1.8 nm diameter embedded in Mn and Ag matrices have been studied as a function of the volume fraction (VFF). While the Co nanoparticles in the Ag matrix show superparamagnetic behavior with T_B=9.5 K (1.5% VFF) and T_B=18.5 K (8.9% VFF), the Co nanoparticles in the antiferromagnetic Mn matrix show a transition peak at ∼65 K in the ZFC/FC susceptibility measurements, and an increase of the coercive fields at low temperature with respect to the Ag matrix. Exchange bias due to the interface exchange coupling between Co particles and the antiferromagnetic Mn matrix has also been studied. The exchange bias field (H_eb), observed for all Co/Mn samples below 40 K, decreases with decreasing volume fraction and with increasing temperature and depends on the field of cooling (H_fc). Exchange bias is accompanied by an increase of coercivity.

Original language	English
Pages (from-to)	155-158
Number of pages	4
Journal	Journal of Magnetism and Magnetic Materials
Volume	316
Issue number	2 SPEC. ISS.
DOIs	https://doi.org/10.1016/j.jmmm.2007.02.058
State	Published - Sep 2007
Externally published	Yes

Funding

This work was supported by EC project NANOSPIN (Contract No. NMP4-CT-2004-013545).

Funders	Funder number
European Commission	NMP4-CT-2004-013545

Keywords

AFM/FM interfaces
Co nanoparticles
Exchange bias
Magnetic stability
Nanoparticles

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10.1016/j.jmmm.2007.02.058

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title = "Exchange bias in Co nanoparticles embedded in an Mn matrix",

abstract = "Magnetic properties of Co nanoparticles of 1.8 nm diameter embedded in Mn and Ag matrices have been studied as a function of the volume fraction (VFF). While the Co nanoparticles in the Ag matrix show superparamagnetic behavior with TB=9.5 K (1.5% VFF) and TB=18.5 K (8.9% VFF), the Co nanoparticles in the antiferromagnetic Mn matrix show a transition peak at ∼65 K in the ZFC/FC susceptibility measurements, and an increase of the coercive fields at low temperature with respect to the Ag matrix. Exchange bias due to the interface exchange coupling between Co particles and the antiferromagnetic Mn matrix has also been studied. The exchange bias field (Heb), observed for all Co/Mn samples below 40 K, decreases with decreasing volume fraction and with increasing temperature and depends on the field of cooling (Hfc). Exchange bias is accompanied by an increase of coercivity.",

keywords = "AFM/FM interfaces, Co nanoparticles, Exchange bias, Magnetic stability, Nanoparticles",

author = "Neus Domingo and Testa, {Alberto M.} and Dino Fiorani and Chris Binns and Stephen Baker and Javier Tejada",

year = "2007",

month = sep,

doi = "10.1016/j.jmmm.2007.02.058",

language = "English",

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pages = "155--158",

journal = "Journal of Magnetism and Magnetic Materials",

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TY - JOUR

T1 - Exchange bias in Co nanoparticles embedded in an Mn matrix

AU - Domingo, Neus

AU - Testa, Alberto M.

AU - Fiorani, Dino

AU - Binns, Chris

AU - Baker, Stephen

AU - Tejada, Javier

PY - 2007/9

Y1 - 2007/9

N2 - Magnetic properties of Co nanoparticles of 1.8 nm diameter embedded in Mn and Ag matrices have been studied as a function of the volume fraction (VFF). While the Co nanoparticles in the Ag matrix show superparamagnetic behavior with TB=9.5 K (1.5% VFF) and TB=18.5 K (8.9% VFF), the Co nanoparticles in the antiferromagnetic Mn matrix show a transition peak at ∼65 K in the ZFC/FC susceptibility measurements, and an increase of the coercive fields at low temperature with respect to the Ag matrix. Exchange bias due to the interface exchange coupling between Co particles and the antiferromagnetic Mn matrix has also been studied. The exchange bias field (Heb), observed for all Co/Mn samples below 40 K, decreases with decreasing volume fraction and with increasing temperature and depends on the field of cooling (Hfc). Exchange bias is accompanied by an increase of coercivity.

AB - Magnetic properties of Co nanoparticles of 1.8 nm diameter embedded in Mn and Ag matrices have been studied as a function of the volume fraction (VFF). While the Co nanoparticles in the Ag matrix show superparamagnetic behavior with TB=9.5 K (1.5% VFF) and TB=18.5 K (8.9% VFF), the Co nanoparticles in the antiferromagnetic Mn matrix show a transition peak at ∼65 K in the ZFC/FC susceptibility measurements, and an increase of the coercive fields at low temperature with respect to the Ag matrix. Exchange bias due to the interface exchange coupling between Co particles and the antiferromagnetic Mn matrix has also been studied. The exchange bias field (Heb), observed for all Co/Mn samples below 40 K, decreases with decreasing volume fraction and with increasing temperature and depends on the field of cooling (Hfc). Exchange bias is accompanied by an increase of coercivity.

KW - AFM/FM interfaces

KW - Co nanoparticles

KW - Exchange bias

KW - Magnetic stability

KW - Nanoparticles

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U2 - 10.1016/j.jmmm.2007.02.058

DO - 10.1016/j.jmmm.2007.02.058

M3 - Article

AN - SCOPUS:34250642790

SN - 0304-8853

VL - 316

SP - 155

EP - 158

JO - Journal of Magnetism and Magnetic Materials

JF - Journal of Magnetism and Magnetic Materials

IS - 2 SPEC. ISS.

ER -

Exchange bias in Co nanoparticles embedded in an Mn matrix

Abstract

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Keywords

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