High-energy product exchange-spring FePt/Fe cluster nanocomposite permanent magnets

Rui, X.; Shield, Jeffrey E.; Sun, Zhiguang; Yue, Lanping; Xu, Ying; Sellmyer, David J.; Liu, Z.; Miller, Dean J.

doi:10.1016/j.jmmm.2005.11.032

Cited by 31 publications

(17 citation statements)

References 28 publications

(31 reference statements)

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“…7 For complete coupling, the dimension of the soft phase must be on the order of twice the domain wall width of the hard magnet phase ͑typi-cally less than 10 nm͒. Nearly ideal exchange coupling between soft and hard magnetic phases has been effectively realized by controlling the dimension of the soft magnetic phase through the fabrication of soft magnetic nanoparticles below 10 nm using chemical self-assembly 8 and gas aggregation 9 approaches. Both approaches resulted in energy products above 20 MG Oe in Fe-Pt nanocomposites, more than 50% greater than expected for isotropic, single-phase noninteracting FePt.…”

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confidence: 99%

In-cluster-structured exchange-coupled magnets with high energy densities

Rui

Shield

Sun

et al. 2006

Applied Physics Letters

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In this letter, the authors demonstrate isotropic Fe–Pt exchange-spring nanocomposite permanent magnets with a soft magnetic phase fraction of greater than 0.5 with a coercivity of 6.5kOe, single-phase-like magnetic behavior, and an energy product of 25.1MGOe. Sub-10-nm Fe–Pt clusters are formed with compositions in the two-phase Fe3Pt and FePt regions. Intracluster structuring on a scale of a few nanometers occurs after appropriate heat treatment. This ensures full exchange coupling between the two phases, allowing greater soft magnetic phase fractions. The results provide insight into developing high energy product nanostructured permanent magnets.

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confidence: 99%

In-cluster-structured exchange-coupled magnets with high energy densities

Rui

Shield

Sun

et al. 2006

Applied Physics Letters

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“…The maximum coercivity was improved from <3 kOe to more than 6 kOe. Furthermore, the energy product improved to 25.1 MGOe, 25 percent higher than previously reported for the Fe 3 Pt/FePt system [2] or Fe/FePt system [8], and the highest ever reported for isotropic Fe-Pt alloys. …”

Section: Fe 3 Pt-fept Systemmentioning

confidence: 51%

“…In all cases the structure displayed random crystallographic orientation.Structural characterization of the nanocomposite structure proved difficult because of the complex microstructure associated with the ordering process. An analysis of the diffusion profile after heat treatment [8] suggested that the heat treatments did not result in dissolution of the Fe clusters.…”

Section: Fe-fept Systemmentioning

confidence: 99%

Cluster-Assembled Iron-Platinum Nanocomposite Permanent Magnets

Rui

Sun

et al. 2006

MRS Proc.

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Exchange-spring nanocomposite permanent magnets have received a great deal of attention for their potential for improved the energy products. Predicted results, however, has been elusive. Optimal properties rely on a uniformly fine nanostructure. Particularly, the soft magnetic phase must be below approximately 10 nm to ensure complete exchange coupling. Inert gas condensation (IGC) is an ideal processing route to produce sub-10 nm clusters method. Two distinct nanostructures have been produced. In the first, Fe clusters were embedded in an FePt matrix by alternate deposition from two sources. Fe cluster content ranged from 0 to 30 volume percent. Post-deposition multi-step heat treatments converted the FePt from the A1 to L1 0 structure. An energy product of approximately 21 MGOe was achieved. Properties deteriorated rapidly at cluster concentrations above 14 volume due to uncoupled soft magnetic regions (from cluster-cluster contacts) and cooperative reversal. The second nanostructure, designed to overcome those disadvantages, involved intra-cluster structuring. Here, Fe-rich Fe-Pt clusters separated by C or SiO 2 were fabricated. Phase separation into Fe 3 Pt and FePt and ordering was induced during post-deposition multi-step heat treatments. By confining the soft and hard phases to individual clusters, full exchange coupling was accomplished and cooperative reversal between clusters was effectively eliminated. An energy product of more than 25 MGOe was achieved, and the volume fraction of the soft phase was increased to greater than 0.5 while maintaining a coercivity of 6.5 kOe. The results provide new insight into developing high energy product nanostructured permanent magnets.

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“…However, the magnetization evaluated per weight 40,41) was indicated and no information on the packing density of cluster assemblies. Since the magnetization per volume is necessary to estimate BH MAX , we cannot compare the present results with the reported ones.…”

Section: Discussionmentioning

confidence: 99%

“…So far, FePt particles and Fe particles/FePt thin film hybrids prepared by cluster deposition methods have been reported to show excellent hard magnetic properties. 40,41) In this study, we prepared FePt cluster/FeCo film and FeCo cluster/FePt film laminated hybrids using both a PGCCD system and a helicon-plasma-type-sputter-deposition system and observed their structures and magnetic properties. Based on these result, we are discussing a perspective of these cluster/film laminated hybrids for the application to spring magnets.…”

Section: )mentioning

confidence: 99%

Magnetic Properties of Cluster/Thin-Film Laminated Hybrids of Fe–Pt and Fe–Co Alloys

et al. 2012

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Both FePt cluster/FeCo film and FeCo cluster/FePt film laminated hybrids have been prepared by combination of a plasma-gascluster-deposition and a helicon-plasma sputter-deposition and studied by X-ray diffraction and magnetization measurements. In FePt cluster/ FeCo film laminated hybrids, M S increases, while H C and BH MAX monotonically decrease with the FeCo film thickness. In FeCo cluster/Fe Pt film laminated hybrids, M S , H C and BH MAX increase with the FeCo cluster layer thickness in comparison with those of simple FePt films. However, the remarkable improvement of their hard magnetic properties cannot be attained in these laminated hybrids owing to both the low packing density of FeCo clusters and the difficulty in the diffusion-control of Fe and Co atoms from FeCo to FePt layers.

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High-energy product exchange-spring FePt/Fe cluster nanocomposite permanent magnets

Abstract: -energy product exchange-spring FePt/Fe cluster nanocomposite permanent magnets" (2006). David Sellmyer Publications. 95.

Cited by 31 publications

References 28 publications

In-cluster-structured exchange-coupled magnets with high energy densities

In-cluster-structured exchange-coupled magnets with high energy densities

Cluster-Assembled Iron-Platinum Nanocomposite Permanent Magnets

Magnetic Properties of Cluster/Thin-Film Laminated Hybrids of Fe–Pt and Fe–Co Alloys

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High-energy product exchange-spring FePt/Fe cluster nanocomposite permanent magnets

Abstract: -energy product exchange-spring FePt/Fe cluster nanocomposite permanent magnets" (2006). David Sellmyer Publications. 95.

Cited by 31 publications

References 28 publications

In-cluster-structured exchange-coupled magnets with high energy densities

In-cluster-structured exchange-coupled magnets with high energy densities

Cluster-Assembled Iron-Platinum Nanocomposite Permanent Magnets

Magnetic Properties of Cluster/Thin-Film Laminated Hybrids of Fe&ndash;Pt and Fe&ndash;Co Alloys

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Product

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Magnetic Properties of Cluster/Thin-Film Laminated Hybrids of Fe–Pt and Fe–Co Alloys