Structural modification and ultra-high coercivity of nanostructural anisotropic MnBi/Bi films

Zhang, Yinfeng; Han, Jingquan; Liu, Shunquan; Tian, Haidong; Zhao, Hui; Du, Honglin; Yang, Yu; Fang, Yikun; Li, Wei; Yang, Jinbo

doi:10.1016/j.actamat.2017.02.012

Cited by 20 publications

(19 citation statements)

References 25 publications

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“…For such systems, in some cases, the values of the coercive field can exceed 3 T at room temperature. Further, the Mn-Bi system is interesting and promising [ 20 , 21 , 22 ], especially the low-temperature phase (LTP), which reveals high magnetocrystalline anisotropy at room temperature. The crystal structure of such a compound (MnBi, sometimes referred to as α-MnBi in the literature) is hexagonal (NiAs-type), as shown in Figure 3 .…”

Section: Brief Review Of High and Ultra-high Coercive Magnetic Materialsmentioning

confidence: 99%

“…Some enhancement of the energy product valued at approximately 200 kJ/m 3 was observed in a bilayer system of MnBi (20 nm of thickness) and Co (3 nm of thickness). A higher coercivity of approximately 2.7 T was reported for thin layers prepared by the pulse laser deposition method [ 21 ].…”

Section: Brief Review Of High and Ultra-high Coercive Magnetic Materialsmentioning

confidence: 99%

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High and Ultra-High Coercive Materials in Spring-Exchange Systems—Review, Simulations and Perspective

Chrobak

2022

Materials

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The paper refers to the spring-exchange magnetic systems containing magnetically soft and hard phases. This work consists of two parts. The first part is a brief review of hard magnetic materials, with special attention paid to ultra-high coercive compounds, as well as selected spring-exchange systems. The second part is a theoretical discussion based on the Monte Carlo micromagnetic simulations about the possible enhancement of the hard magnetic properties of systems composed of magnetically soft, as well as high and ultra-high coercive, phases. As shown, the analyzed systems reveal the potential for improving the |BH|max parameter, filling the gap between conventional and Nd-based permanent magnets. Moreover, the carried-out simulations indicate the advantages and limitations of the spring-exchange composites, which could lead to a reduction in rare earth elements in permanent magnet applications.

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Section: Brief Review Of High and Ultra-high Coercive Magnetic Materialsmentioning

confidence: 99%

Section: Brief Review Of High and Ultra-high Coercive Magnetic Materialsmentioning

confidence: 99%

High and Ultra-High Coercive Materials in Spring-Exchange Systems—Review, Simulations and Perspective

Chrobak

2022

Materials

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“…There is still a room to improve the coercvity of MnBi after ball milling. Furthermore, the contribution of SALEBM and the effect of surface defects on magnetization, coercivity are deserved to investigate further [20,21].…”

Section: Ofmentioning

confidence: 99%

Microstructure and Magnetic Properties of Mn55Bi45 Powders Obtained by Different Ball Milling Processes

Dong

Xiang

et al. 2019

Metals

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Low-temperature phase (LTP) MnBi is considered as a promising rare-earth-free permanent magnetic material with high coercivity and unique positive temperature coefficient of coercivity. Mn55Bi45 ribbons with high purity of LTP MnBi phase were prepared by melt spinning. Then, Mn55Bi45 powders with different particle size were obtained by low-energy ball milling (LEBM) with and without added surfactant. The coercivity is enhanced in both cases. Microstructure characterization reveals that Mn55Bi45 powders obtained by surfactant assisted low-energy ball milling (SALEBM) have better particle size uniformity and show higher decomposition of LTP MnBi. Coercivity can achieve a value of 17.2 kOe and the saturation magnetization (Ms) is 16 emu/g when Mn55Bi45 powders milled about 10 h by SALEBM. Coercivity has achieved a maximum value of 18.2 kOe at room temperature, and 23.5 kOe at 380 K after 14 h of LEBM. Furthermore, Mn55Bi45 powders obtained by LEBM have better magnetic properties.

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“…It presents profound engineering properties at small clusters of single magnetic domains (SMDs) in three major forms; bulk, thin films, and nano-architects (NAs). Traditionally, it is believed to form and exist of a line compound Mn 50 Bi 50 of crystallites at equal Mn/Bi atoms [9][10][11][12][13][14][15][16][17]. Then, a question arises how a Mn/Bi ratio keeps as the atoms converge at surfaces at NAs in small clusters [19,22].…”

Section: Introductionmentioning

confidence: 99%

“…Collective spins at small core-shells can interplay a vital role in determining the crystal field anisotropy K 1 , phase stability, united spin dynamics, and other functional properties. Collinear 3d 5 -Mn spins (a low temperature α-phase) at the stoichiometry Mn 50+x Bi 50-x , x → 0, a NiAs-type hexagonal (h) crystal structure (P6 3 /mmc space group), give a spin magnetic moment μ s = 3.95 μ B per Mn (83.5 emu g −1 ) at room temperature [10,12]. A magnetostructural transition is known to result in a high-temperature Mn 1+δ Bi, δ → 0.08, β-phase at 628 K (Curie point T C at the αphase), of a paramagnet (PM) state [2,5].…”

Section: Introductionmentioning

confidence: 99%

A core–shell magnet Mn₇₀Bi₃₀ grown at seeds in magnetic fields and its impacts on its spin-dynamics, Curie point and other tailored properties

2023

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The MnBi alloys is a model series of rare-earth free magnets for surge of technologies of small parts of automobiles, power generators, medical tools, memory systems, and many others. The magnetics stem primarily at unpaired Mn-3d5 spins (a 4.23 B moment) align parallel via an orbital moment 0.27 B of Bi-5d106s2p3 in a crystal lattice. Thus, using a surplus Mn (over Bi) in a Mn70Bi30 type alloy designs a spin-rich system of duly tailored properties useful for magnetics and other devices. In this view, we report here a strategy of a refined alloy powder Mn70Bi30 can grow into small crystals of hexagonal (h) plates at seeds as annealed in magnetic fields (in H2 gas). So, small h-plates (30 to 50 nm widths) are grown up at (002) facets, wherein the edges are turned down in a spiral ( 2.1 nm thicknesses) in a core-shell structure. The results are described with X-ray diffraction, lattice images and magnetic properties of a powder Mn70Bi30 (milled in glycine) is annealed at 573 K for different time periods, so to the Mn/Bi order at the permeable facets (seeds). Duly annealed samples exhibit an enhanced magnetization, Ms  70.8 emu/g, with duly promoted coercivity Hc  10.810 kOe (15.910 kOe at 350 K), energy–product 14.8 MGOe, and the crystal-field-anisotropy, K1  7.6x107 erg/cm3, reported at room temperature. Otherwise, Ms should decline at any surplus 3d5-Mn spins order antiparallel at the antisites. Enhanced Curie point 658.1 K (628 K at Mn50Bi50 alloy) anticipates that a surplus Mn does favor the Mn-Bi exchange interactions. Proposed spin models well describe the spin-dynamics and lattice relaxations (on anneals) over the lattice volume (with twins) and spin clusters.

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Structural modification and ultra-high coercivity of nanostructural anisotropic MnBi/Bi films

Cited by 20 publications

References 25 publications

High and Ultra-High Coercive Materials in Spring-Exchange Systems—Review, Simulations and Perspective

High and Ultra-High Coercive Materials in Spring-Exchange Systems—Review, Simulations and Perspective

Microstructure and Magnetic Properties of Mn55Bi45 Powders Obtained by Different Ball Milling Processes

A core–shell magnet Mn₇₀Bi₃₀ grown at seeds in magnetic fields and its impacts on its spin-dynamics, Curie point and other tailored properties

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Structural modification and ultra-high coercivity of nanostructural anisotropic MnBi/Bi films

Cited by 20 publications

References 25 publications

High and Ultra-High Coercive Materials in Spring-Exchange Systems—Review, Simulations and Perspective

High and Ultra-High Coercive Materials in Spring-Exchange Systems—Review, Simulations and Perspective

Microstructure and Magnetic Properties of Mn55Bi45 Powders Obtained by Different Ball Milling Processes

A core–shell magnet Mn70Bi30 grown at seeds in magnetic fields and its impacts on its spin-dynamics, Curie point and other tailored properties

Contact Info

Product

Resources

About

A core–shell magnet Mn₇₀Bi₃₀ grown at seeds in magnetic fields and its impacts on its spin-dynamics, Curie point and other tailored properties