Effects of Mg and Sb Substitution on the Magnetic Properties of Magnetic Field Annealed MnBi Alloys
1
Powder & Ceramics Division, Korea Institute of Materials Science, Changwon 51508, Korea
2
School of Materials Science and Engineering, Pusan National University, Busan 46241, Korea
*
Authors to whom correspondence should be addressed.
Nanomaterials 2020, 10(11), 2265; https://doi.org/10.3390/nano10112265
Received: 20 October 2020
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Revised: 4 November 2020
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Accepted: 13 November 2020
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Published: 16 November 2020
(This article belongs to the Special Issue Synthesis and Properties of Nanocrystalline Magnetic Materials)
Rare-earth-free permanent magnets have attracted considerable attention due to their favorable properties and applicability for cost-effective, high-efficiency, and sustainable energy devices. However, the magnetic field annealing process, which enhances the performance of permanent magnets, needs to be optimized for different magnetic fields and phases. Therefore, we investigated the effect of composition on the crystallization of amorphous MnBi to the ferromagnetic low-temperature phase (LTP). The optimal compositions and conditions were applied to magnetic field annealing under 2.5 T for elemental Mg- and Sb/Mg pair-substituted MnBi. The optimum MnBi composition for the highest purity LTP was determined to be Mn56Bi44, and its maximum energy product, (BH)max, was 5.62 MGOe. The Mg-substituted MnBi exhibited enhanced squareness (Mr/Ms), coercivity (Hc), and (BH)max values up to 0.8, 9659 Oe, and 5.64 MGOe, respectively, whereas the same values for the Sb/Mg pair-substituted MnBi were 0.76, 7038 Oe, and 5.60 MGOe, respectively. The substitution effects were also investigated using first-principles calculations. The density of states and total magnetic moments of Mn16Bi15Mg and Mn16Bi15Sb were similar to those of pure Mn16Bi16. Conversely, the Sb-substituted MnBi resulted in a dramatic enhancement in the anisotropy constant (K) from a small negative value (−0.85 MJ/m3) to a large positive value (6.042 MJ/m3).
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MDPI and ACS Style
Qian, H.-D.; Yang, Y.; Lim, J.T.; Kim, J.-W.; Choi, C.-J.; Park, J. Effects of Mg and Sb Substitution on the Magnetic Properties of Magnetic Field Annealed MnBi Alloys. Nanomaterials 2020, 10, 2265. https://doi.org/10.3390/nano10112265
AMA Style
Qian H-D, Yang Y, Lim JT, Kim J-W, Choi C-J, Park J. Effects of Mg and Sb Substitution on the Magnetic Properties of Magnetic Field Annealed MnBi Alloys. Nanomaterials. 2020; 10(11):2265. https://doi.org/10.3390/nano10112265
Chicago/Turabian StyleQian, Hui-Dong, Yang Yang, Jung T. Lim, Jong-Woo Kim, Chul-Jin Choi, and Jihoon Park. 2020. "Effects of Mg and Sb Substitution on the Magnetic Properties of Magnetic Field Annealed MnBi Alloys" Nanomaterials 10, no. 11: 2265. https://doi.org/10.3390/nano10112265
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