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Controlling exchange bias in Fe3O4/FeO composite particles prepared by pulsed laser irradiation.

Swiatkowska-Warkocka Z, Kawaguchi K, Wang H, Katou Y, Koshizaki N - Nanoscale Res Lett (2011)

Bottom Line: Through tuning the laser fluence, the Fe3O4/FeO phase ratio can be precisely controlled, and the magnetic properties of final products can also be regulated.This work presents a successful example of the fabrication of ferro (ferri) (FM)/antiferromagnetic (AFM) systems with high chemical stability.The results show this novel simple method as widely extendable to various FM/AFM nanocomposite systems.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8565 Ibaraki, Japan. zaneta.swiatkowska@aist.go.jp.

ABSTRACT
Spherical iron oxide nanocomposite particles composed of magnetite and wustite have been successfully synthesized using a novel method of pulsed laser irradiation in ethyl acetate. Both the size and the composition of nanocomposite particles are controlled by laser irradiation condition. Through tuning the laser fluence, the Fe3O4/FeO phase ratio can be precisely controlled, and the magnetic properties of final products can also be regulated. This work presents a successful example of the fabrication of ferro (ferri) (FM)/antiferromagnetic (AFM) systems with high chemical stability. The results show this novel simple method as widely extendable to various FM/AFM nanocomposite systems.

No MeSH data available.


Related in: MedlinePlus

Variation of Hc and Hexch. Coercivity Hc and exchange bias Hexch of Fe3O4/FeO composite particles as a function of relative fraction of FeO in particles measured at 5 K.
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Figure 6: Variation of Hc and Hexch. Coercivity Hc and exchange bias Hexch of Fe3O4/FeO composite particles as a function of relative fraction of FeO in particles measured at 5 K.

Mentions: To reveal the effect of the phase ratio of FM and AFM phase on the exchange bias of FM/AFM composites, Hc and Hexch as a function of FeO phase ratio in Fe3O4/FeO particles was investigated. Figure 6 shows the variation of Hc (after ZFC) and Hexch (after FC in 50 kOe) with the increase FeO fraction in particles at 5 K. It is clear that Hc increases with the increasing FeO fraction, while Hexch firstly increases and then reaches a maximum of 1,960 Oe for 75% of wustite fraction. Further increase of FeO concentration leads to the decrease of Hexch. With increasing FeO concentration, the AFM phase can supply enough force to pin the uncompensated spin in FM phase which leads to a much stronger exchange interaction and further increase in Hexch. With a further increase in FeO concentration (> 75%), the balance between FM and AFM is destroyed, and Hexch do not increase continuously with increasing FeO concentration. In this case, 75% is a critical concentration of AF phase in Fe3O4/FeO composites. This result can confirm granular structure of obtained particles. With increasing FeO phase the effective interface area increases affecting exchange bias. AFM is too high for 75% of FeO concentration, and the effective interface area rapidly decreases entailing the exchange bias decrease


Controlling exchange bias in Fe3O4/FeO composite particles prepared by pulsed laser irradiation.

Swiatkowska-Warkocka Z, Kawaguchi K, Wang H, Katou Y, Koshizaki N - Nanoscale Res Lett (2011)

Variation of Hc and Hexch. Coercivity Hc and exchange bias Hexch of Fe3O4/FeO composite particles as a function of relative fraction of FeO in particles measured at 5 K.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211284&req=5

Figure 6: Variation of Hc and Hexch. Coercivity Hc and exchange bias Hexch of Fe3O4/FeO composite particles as a function of relative fraction of FeO in particles measured at 5 K.
Mentions: To reveal the effect of the phase ratio of FM and AFM phase on the exchange bias of FM/AFM composites, Hc and Hexch as a function of FeO phase ratio in Fe3O4/FeO particles was investigated. Figure 6 shows the variation of Hc (after ZFC) and Hexch (after FC in 50 kOe) with the increase FeO fraction in particles at 5 K. It is clear that Hc increases with the increasing FeO fraction, while Hexch firstly increases and then reaches a maximum of 1,960 Oe for 75% of wustite fraction. Further increase of FeO concentration leads to the decrease of Hexch. With increasing FeO concentration, the AFM phase can supply enough force to pin the uncompensated spin in FM phase which leads to a much stronger exchange interaction and further increase in Hexch. With a further increase in FeO concentration (> 75%), the balance between FM and AFM is destroyed, and Hexch do not increase continuously with increasing FeO concentration. In this case, 75% is a critical concentration of AF phase in Fe3O4/FeO composites. This result can confirm granular structure of obtained particles. With increasing FeO phase the effective interface area increases affecting exchange bias. AFM is too high for 75% of FeO concentration, and the effective interface area rapidly decreases entailing the exchange bias decrease

Bottom Line: Through tuning the laser fluence, the Fe3O4/FeO phase ratio can be precisely controlled, and the magnetic properties of final products can also be regulated.This work presents a successful example of the fabrication of ferro (ferri) (FM)/antiferromagnetic (AFM) systems with high chemical stability.The results show this novel simple method as widely extendable to various FM/AFM nanocomposite systems.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8565 Ibaraki, Japan. zaneta.swiatkowska@aist.go.jp.

ABSTRACT
Spherical iron oxide nanocomposite particles composed of magnetite and wustite have been successfully synthesized using a novel method of pulsed laser irradiation in ethyl acetate. Both the size and the composition of nanocomposite particles are controlled by laser irradiation condition. Through tuning the laser fluence, the Fe3O4/FeO phase ratio can be precisely controlled, and the magnetic properties of final products can also be regulated. This work presents a successful example of the fabrication of ferro (ferri) (FM)/antiferromagnetic (AFM) systems with high chemical stability. The results show this novel simple method as widely extendable to various FM/AFM nanocomposite systems.

No MeSH data available.


Related in: MedlinePlus