Anisotropic nanocrystalline MnBi with high coercivity at high temperature
Anisotropic nanocrystalline MnBi with high coercivity at high temperature
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高温下具有高矫顽力的各向异性纳米晶MnBi
DOI：
10.1063/1.3630001
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发表时间：
2011-08-22
影响因子：
4
通讯作者：
Chen, D. F.
中科院分区：
文献类型：
--
作者：
Yang, J. B.;Yang, Y. B.;Chen, D. F.
通过熔融纺丝和随后的低温退火制备了磁性硬纳米晶MnBi。对于平均晶粒尺寸约为20-30 nm的MnBi，在540 K时可以实现2.5 T的矫顽力。矫顽力 iH(c) 主要由相干磁化旋转控制，表现出对研磨时间的强烈依赖性，并在 100 至 540 K 范围内表现出正温度系数。矫顽力（磁晶各向异性）的独特温度依赖性行为与 c/a 晶格比随温度的变化有关。此外，在磁结构转变温度下，a、c和c/a比的晶格参数未发现不连续性。固定在环氧树脂中并在 24 kOe 的外加磁场下固定的纳米晶 MnBi 粉末在室温下表现出 7.1 MGOe 的最大磁能积，并表现出各向异性特性，Mr/Ms 比高达 560 K。 (C) 2011 美国物理研究所。 [doi:10.1063/1.3630001]
Magnetic hard nanocrystalline MnBi has been prepared by melt spinning and subsequent low temperature annealing. A coercivity of 2.5 T can be achieved at 540 K for MnBi with an average grain size of about 20-30 nm. The coercivity iH(c), mainly controlled by the coherent magnetization rotation, shows a strong dependence on the time of grinding and exhibits a positive temperature coefficient from 100 up to 540 K. The unique temperature dependent behavior of the coercivity (magnetocrystalline anisotropy) has a relationship with the variations in the crystal lattice ratio of c/a with temperatures. In addition, discontinuity can not be found in the lattice parameters of a, c, and c/a ratio at the magnetostructural transition temperature. The nanocrystalline MnBi powder fixed in an epoxy resin and under an applied magnetic field of 24 kOe shows a maximum energy product of 7.1 MGOe at room temperature and shows anisotropic characteristics with high Mr/Ms ratio up to 560 K. (C) 2011 American Institute of Physics. [doi:10.1063/1.3630001]