Simultaneously increasing the magnetization and coercivity of bulk nanocomposite magnets via severe plastic deformation

Li, Yong; Lou, Li; Hou, Fuchen; Guo, Defeng; Li, Wei; Li, Xiaohong; Гундеров, Д. В.; Sato, K.; Zhang, Xiangyi

doi:10.1063/1.4824032

Cited by 82 publications

(27 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We further determined the coercivity mechanism of the material that involves domain‐wall pinning (Figure S3, Supporting Information). This result is likely to originate from the abundant grain boundaries from the small nanosized hard and soft grains that increase the number of domain‐wall‐pinning sites; moreover, the observed SmCo 3 phase (≈9 wt% determined by XRD studies) in the material may also contribute to the strong pinning behavior by increasing grain boundary fraction or forming stacking faults as pining centers, as demonstrated in recent studies of ultrahigh coercivity Sm−Co thin films . This result suggests the way to enhance the coercivity of the materials by increasing domain‐wall‐pinning strength and sites.…”

mentioning

confidence: 60%

Novel Bimorphological Anisotropic Bulk Nanocomposite Materials with High Energy Products

et al. 2017

Self Cite

View full text Add to dashboard Cite

Nanostructuring of magnetically hard and soft materials is fascinating for exploring next-generation ultrastrong permanent magnets with less expensive rare-earth elements. However, the resulting hard/soft nanocomposites often exhibit random crystallographic orientations and monomorphological equiaxed grains, leading to inferior magnetic performances compared to corresponding pure rare-earth magnets. This study describes the first fabrication of a novel bimorphological anisotropic bulk nanocomposite using a multistep deformation approach, which consists of oriented hard-phase SmCo rod-shaped grains and soft-phase Fe(Co) equiaxed grains with a high fraction (≈28 wt%) and small size (≈10 nm). The nanocomposite exhibits a record-high energy product (28 MGOe) for this class of bulk materials with less rare-earth elements and outperforms, for the first time, the corresponding pure rare-earth magnet with 58% enhancement in energy product. These findings open up the door to moving from a pure permanent-magnet system to a stronger nanocomposite system at lower costs.

show abstract

mentioning

confidence: 60%

Novel Bimorphological Anisotropic Bulk Nanocomposite Materials with High Energy Products

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the other hand, H c initially increases from 8.65 kOe to 10.1 kOe on increasing the soft phase content from 0 to 0.07, and then continuously decreases on further addition of the soft phase. The initial increase of H c reflects the formation of the composite nanostructure and is probably caused by reduced real-structure imperfections upon surface coating and/or a comparatively better easy-axis alignment 32 .…”

Section: Resultsmentioning

confidence: 99%

Magnetic nanostructuring and overcoming Brown's paradox to realize extraordinary high-temperature energy products

Balamurugan

Mukherjee

Skomski

et al. 2014

Sci Rep

View full text Add to dashboard Cite

Nanoscience has been one of the outstanding driving forces in technology recently, arguably more so in magnetism than in any other branch of science and technology. Due to nanoscale bit size, a single computer hard disk is now able to store the text of 3,000,000 average-size books, and today's high-performance permanent magnets—found in hybrid cars, wind turbines, and disk drives—are nanostructured to a large degree. The nanostructures ideally are designed from Co- and Fe-rich building blocks without critical rare-earth elements, and often are required to exhibit high coercivity and magnetization at elevated temperatures of typically up to 180 °C for many important permanent-magnet applications. Here we achieve this goal in exchange-coupled hard-soft composite films by effective nanostructuring of high-anisotropy HfCo7 nanoparticles with a high-magnetization Fe65Co35 phase. An analysis based on a model structure shows that the soft-phase addition improves the performance of the hard-magnetic material by mitigating Brown's paradox in magnetism, a substantial reduction of coercivity from the anisotropy field. The nanostructures exhibit a high room-temperature energy product of about 20.3 MGOe (161.5 kJ/m3), which is a record for a rare earth- or Pt-free magnetic material and retain values as high as 17.1 MGOe (136.1 kJ/m3) at 180°C.

show abstract

“…First, a Henkel plot was used to obtain the δm value (see the Experimental Section), which is generally used to characterize the exchange‐coupling strength of magnetic grains . A value of δm = 1.4 was achieved ( Figure a), which is larger than that of the corresponding two‐component SmCo/FeCo nanostructure ( δm = 1.1; Figure a) and much larger than the reported values for NdFeB/FeCo nanocomposite magnets with high fractions (≥20 wt%) of the soft phase ( δm = 0.2−0.6) . Given that the multicomponent material without a layered structure exhibits two‐phase magnetization behavior (Figure S7, Supporting Information), we suggest that the layered architecture makes a significant contribution to the observed strong exchange coupling between the soft and hard magnetic grains.…”

mentioning

confidence: 93%

Engineering Bulk, Layered, Multicomponent Nanostructures with High Energy Density

Huang

Lou

et al. 2018

Small

Self Cite

View full text Add to dashboard Cite

The precise control of individual components in multicomponent nanostructures is crucial to realizing their fascinating functionalities for applications in electronics, energy-conversion devices, and biotechnologies. However, this control remains particularly challenging for bulk, multicomponent nanomaterials because the desired structures of the constitute components often conflict. Herein, a strategy is reported for simultaneously controlling the structural properties of the constituent components in bulk multicomponent nanostructures through layered structural design. The power of this approach is illustrated by generating the desired structures of each constituent in a bulk multicomponent nanomaterial (SmCo + FeCo)/NdFeB, which cannot be attained with existing methods. The resulting nanostructure exhibits a record high energy density (31 MGOe) for this class of bulk nanocomposites composed of both hard and soft magnetic materials, with the soft magnetic fraction exceeding 20 wt%. It is anticipated that other properties beyond magnetism, such as the thermoelectric and mechanical properties, can also be tuned by engineering such layered architectures.

show abstract

Simultaneously increasing the magnetization and coercivity of bulk nanocomposite magnets via severe plastic deformation

Cited by 82 publications

References 22 publications

Novel Bimorphological Anisotropic Bulk Nanocomposite Materials with High Energy Products

Novel Bimorphological Anisotropic Bulk Nanocomposite Materials with High Energy Products

Magnetic nanostructuring and overcoming Brown's paradox to realize extraordinary high-temperature energy products

Engineering Bulk, Layered, Multicomponent Nanostructures with High Energy Density

Contact Info

Product

Resources

About