Energy barrier and magnetic properties of exchange-coupled hard-soft bilayer

Shan, Z.S.; Liu, J.P.; Chakka, V. M.; Zeng, Hao; Jiang, J. S.

doi:10.1109/tmag.2002.803226

Cited by 44 publications

(28 citation statements)

References 8 publications

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“…1,2,19,20 This critical dimension is the upper limit for all the soft-phase grains ͑not an average of the distribution͒. Our calculation gave the critical dimension of ϳ20 nm for the Fe-based soft phase in the SmCo 5 matrix.…”

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confidence: 70%

Fabrication of bulk nanocomposite magnets via severe plastic deformation and warm compaction

Rong

Zhang

Poudyal

et al. 2010

Applied Physics Letters

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We demonstrate that a SmCo/FeCo based hard/soft nanocomposite material can be fabricated by distributing the soft magnetic ␣-Fe phase particles homogeneously in a hard magnetic SmCo phase through severe plastic deformation. The soft-phase particle size can be reduced from micrometers to smaller than 15 nm upon deformation. Up to 30% of the soft phase can be incorporated into the composites without coarsening. A warm compaction process of the plastically deformed powder particles then produces bulk nanocomposite magnets of fully dense nanocomposites with energy product up to 19.2 MGOe owing to effective interphase exchange coupling, which makes this type of nanocomposite magnets suitable for high energy-density applications at high temperatures.

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mentioning

confidence: 70%

Fabrication of bulk nanocomposite magnets via severe plastic deformation and warm compaction

Rong

Zhang

Poudyal

et al. 2010

Applied Physics Letters

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“…This characteristic demonstrates the non-complete exchange coupling. According to the theoretical calculations, the exchange coupling will be beneficial to the magnetic properties, only if the dimension of the soft phase is not larger than a critical length which is typically twice or less than the domain wall width of the hard phase [3,[30][31][32][33]. The domain wall width of the SrFe 12 O 19 hard ferrite is approximately 9 nm [34].…”

Section: Tem Analysismentioning

confidence: 99%

Synthesis and magnetic properties of hard/soft SrFe12O19/Ni0.7Zn0.3Fe2O4 nanocomposite magnets

Radmanesh

Ebrahimi

2012

Journal of Magnetism and Magnetic Materials

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“…5,6 Effective interphase magnetic exchange coupling in the nanocomposites can be achieved if dimensions of the soft-phase components are not larger than a nanoscale critical length. [7][8][9][10][11][12] The grain size in nanocomposite magnets fabricated by conventional topdown methods, including mechanical alloying and rapid quenching, usually has a wide distribution, and can hardly be controlled below the critical length. An alternative bottom-up approach therefore is necessary to fabricate nanocomposite magnets with controllable nanoscale morphology.…”

Section: Introductionmentioning

confidence: 99%

Bulk FePt-based nanocomposite magnets with enhanced exchange coupling

Rong

Nandwana

Poudyal

et al. 2007

Journal of Applied Physics

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High density bulk FePt/ Fe 3 Pt nanocomposite magnets have been prepared by high-pressure warm compaction of chemically synthesized FePt and Fe 3 O 4 nanoparticles. It is found that the density increases with the compaction pressure and temperature. Density of the bulk samples up to 95% theoretical value has been obtained while the nanostructured morphology is retained. It is also observed that a high pressure expedites the FePt phase transition from the disordered face-centered-cubic structure to the L1 0 structure, leading to the phase transition temperature in the compacts one hundred degrees lower than usual. This phase transition in turn facilitates the consolidation of the compacts. Magnetic characterizations showed that interphase exchange coupling is enhanced upon the compaction. Post-annealing of the compacts results in further improved magnetic performance of the compacts owing to interface modification. Energy products up to 16.3 MG Oe of the isotropic bulk nanocomposite magnets have been achieved, which is significantly higher than the theoretical limit for fully dense single-phase FePt magnets.

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Energy barrier and magnetic properties of exchange-coupled hard-soft bilayer

Cited by 44 publications

References 8 publications

Fabrication of bulk nanocomposite magnets via severe plastic deformation and warm compaction

Fabrication of bulk nanocomposite magnets via severe plastic deformation and warm compaction

Synthesis and magnetic properties of hard/soft SrFe12O19/Ni0.7Zn0.3Fe2O4 nanocomposite magnets

Bulk FePt-based nanocomposite magnets with enhanced exchange coupling

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