Magnetic properties of the MnBi intermetallic compound

Yang, Jinbo; Kamaraju, Kishore; Yelon, W. B.; James, William Joseph; Cai, Q.; Bollero, A.

doi:10.1063/1.1405434

Cited by 151 publications

(74 citation statements)

References 15 publications

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“…The lattice parameters a and c were determined to be 0.4310 nm and 0.6076 nm at RT, respectively, which are comparable to the reported data of the LTP phase. 4,5,[7][8][9][10][11][12] Using a Farady-force magnetometer, magnetization M was measured in the temperature range from 300 to 620 K and in magnetic fields up to 10 T. The experimental setup of the magnetization measurements was described in Ref. 13) in detail.…”

Section: Methodsmentioning

confidence: 99%

Magnetic Phase Transition of MnBi under High Magnetic Fields and High Temperature

et al. 2007

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Magnetization measurements and differential thermal analysis (DTA) of polycrystalline MnBi were carried out in magnetic fields up to 14 T and in 300-773 K, in order to investigate the magnetic phase transition. The magnetic phase transition temperature (T t ) at a zero magnetic field is 628 K and linearly increases with increasing fields up to 14 T at the rate of 2 KT À1 . A metamagnetic transition between the paramagnetic and field-induced ferromagnetic states was observed just above T t . The exothermic and endothermic peaks were detected in the magnetic field dependence of DTA signals in 626-623 K, which relates to the metamagnetic transition. The obtained results were discussed on the basis of a mean field theory.

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Section: Methodsmentioning

confidence: 99%

Magnetic Phase Transition of MnBi under High Magnetic Fields and High Temperature

et al. 2007

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“…MnBi is an attractive alternative to the permanent magnets containing rare earth elements, especially the ones for medium temperature applications (423-473 K) such as Nd-Fe-B-Dy and Sm-Co. MnBi has attractive temperature properties: its coercivity increases with increasing temperature, reaching a maximum of 2.6 T at 523 K [1][2][3][4]. The high coercivity is attributed to MnBi's large magnetocrystalline anisotropy (1.6 × 10 6 J m −3 ) [5].…”

Section: Introductionmentioning

confidence: 99%

“…A rather drastic peritectic reaction exists over wide temperature and composition ranges. Several methods have been utilized in preparation of high purity MnBi single phase, including arc-melting, sintering, and melt-spin rapid solidification [4,[8][9][10][11]. Among them, only rapid solidification was able to consistently produce over 90% pure MnBi single phase.…”

Section: Introductionmentioning

confidence: 99%

Thermal stability of MnBi magnetic materials

Cui

Choi

et al. 2014

J. Phys.: Condens. Matter

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MnBi has attracted much attention in recent years due to its potential as a rare-earth-free permanent magnet material. It is unique because its coercivity increases with increasing temperature, which makes it a good hard phase material for exchange coupling nanocomposite magnets. MnBi phase is difficult to obtain, partly because the reaction between Mn and Bi is peritectic, and partly because Mn reacts readily with oxygen. MnO formation is irreversible and harmful to magnet performance. In this paper, we report our efforts toward developing MnBi permanent magnets. To date, high purity MnBi (>90%) can be routinely produced in large quantities. The produced powder exhibits 74.6?emu?g?1 saturation magnetization at room temperature with 9?T applied field. After proper alignment, the maximum energy product (BH)max of the powder reached 11.9?MGOe, and that of the sintered bulk magnet reached 7.8?MGOe at room temperature. A comprehensive study of thermal stability shows that MnBi powder is stable up to 473?K in air. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. AbstractMnBi has attracted much attention in recent years due to its potential as a rare-earth-free permanent magnet material. It is unique because its coercivity increases with increasing temperature, which makes it a good hard phase material for exchange coupling nanocomposite magnets. MnBi phase is difficult to obtain, partly because the reaction between Mn and Bi is peritectic, and partly because Mn reacts readily with oxygen. MnO formation is irreversible and harmful to magnet performance. In this paper, we report our efforts toward developing MnBi permanent magnets. To date, high purity MnBi (>90%) can be routinely produced in large quantities. The produced powder exhibits 74.6 emu g −1 saturation magnetization at room temperature with 9 T applied field. After proper alignment, the maximum energy product (BH) max of the powder reached 11.9 MGOe, and that of the sintered bulk magnet reached 7.8 MGOe at room temperature. A comprehensive study of thermal stability shows that MnBi powder is stable up to 473 K in air.

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“…For example, the nominal or intrinsic energy product for thin films is calculated in the standard way from the maximum product of B and H in the second 24,25 These values are the highest among permanent-magnet alloys not containing critical rare-earth elements or expensive Pt; 24,25,[41][42][43][44][45] they also are comparable with the energy product (20.1 MGOe) obtained for chemically prepared exchange-coupled FePtFe 3 Pt nanoparticle assemblies. 1 In addition, the low temperature coefficients of the high-anisotropy nanoclusters also result in appreciable energy products at elevated temperatures.…”

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confidence: 62%

Novel structures and physics of nanomagnets (invited)

Sellmyer

Balamurugan

Das

et al. 2015

Journal of Applied Physics

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Nanoscale magnets with characteristic dimensions in the range of 1–100 nm are important in several areas of nanoscience and technology. First, this length scale spans the typical important dimensions of exchange lengths and domain-wall widths, which means that significant control of magnetic properties can be obtained by varying grain or particle dimensions. Second, the nonequilibrium synthetic processes used for clusters, particles, and films, often lead to new real-space crystal structures with completely novel spin structures and magnetic properties. Third, a basic-science challenge in this class of matter involves the spin-polarized quantum mechanics of many-electron systems containing 10–10 000 atoms. Finally, the materials under study may have important future applications in high-density data storage, ultra-small spintronic devices, or high-energy magnetic materials. In this article, we discuss our recent work on novel Fe-Au nanoclusters, MnAu-Mn core-shell structures, and complex high-anisotropy Co-rich intermetallic compound clusters. We also present new results on Fe-based alloys including the magnetic properties of semiconducting FeSi2 nanoclusters and spin correlations in FeGe nanocluster films.

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Magnetic properties of the MnBi intermetallic compound

Cited by 151 publications

References 15 publications

Magnetic Phase Transition of MnBi under High Magnetic Fields and High Temperature

Magnetic Phase Transition of MnBi under High Magnetic Fields and High Temperature

Thermal stability of MnBi magnetic materials

Novel structures and physics of nanomagnets (invited)

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