Thermal stability of MnBi magnetic materials
| Autor: | H. Reeve, Nikolay A. Zarkevich, J. P. Liu, Matthew J. Olszta, Mark E. Bowden, Nicole R. Overman, Evgueni Polikarpov, Daniel K. Schreiber, Ichiro Takeuchi, Timothy C. Droubay, Jens T. Darsell, N. V. Vuong, Guosheng Li, Hui Wu, Jung-Pyung Choi, Matthew J. Kramer, Qingzhen Huang, Jinfang Cui, Duane D. Johnson, Lin-Lin Wang, M. Marinescu |
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| Rok vydání: | 2014 |
| Předmět: |
Manganese
Nanocomposite Materials science Magnetic Phenomena Thermal decomposition Temperature Coercivity Condensed Matter Physics Nuclear magnetic resonance Magnet Phase (matter) Magnets Coupling (piping) General Materials Science Thermal stability Composite material Bismuth Temperature coefficient Mechanical Phenomena |
| Zdroj: | Journal of Physics: Condensed Matter. 26:064212 |
| ISSN: | 1361-648X 0953-8984 |
| DOI: | 10.1088/0953-8984/26/6/064212 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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