1:12富铁稀土合金化合物的相变和磁性能研究（英文）

【作者】 千辉东； 韩景致； 徐庆； 杨金波； Park Jihoon； Choi Chul-jin；

【机构】 北京大学物理学院,人工微结构和介观物理国家重点实验室； 北京大学凝聚态物理与材料物理研究所； 北京市磁电功能材料与器件重点实验室； 北京大学长三角光电科学研究院； 韩国材料研究院(KIMS)；

【摘要】 Rare-earth intermetallic compounds of R（Fe,M）₁₂（R = rare earth elements, M = transition metals） with ThMn₁₂ structure have been known to be promising permanent magnetic materials since the 1980s [1]. Recently, increasing demand for R has pushed the industry to seek ways to reduce the R-content in hard magnetic materials. In case, strong magnets with the ThMn₁₂ type of structure received much attention [2]. However, during the several tens of years, the research about ThMn₁₂ magnetic materials was not made a breakthrough, due to the rapid development of Nd₂Fe₁₄B. As a turning point of the ThMn₁₂-type Fe-rich compounds research, ThMn₁₂-type Sm(Fe_1-xCo_x)₁₂ compound films with a saturation magnetization of 1.78 T, an anisotropy field of 12 T, and a Curie temperature of 586 °C, all of which are superior to those for Nd₂Fe₁₄B [3], were successfully produced. However, it still has difficulty in stabilizing the unstable ThMn₁₂ phase in fabricating magnetic powders and bulks. In previous research, the ThMn₁₂ structure is also metastable and partial Fe atoms must be substituted with phase stabilizing element（s）, such as Ti, V, Cr, Mn, Mo, W, Al, and Si, which results in magnetization reduction. So, decreasing magnetization or coercivity with the non-magnetic elements substitution is a new challenge for the ThMn₁₂-type Sm(Fe_1-xCo_x)₁₂ compound research. Therefore, we have developed a new fabrication method to produce a high-density Sm(Fe_0.8Co_0.2)₁₁Ti bulk with high purity and magnetic properties and investigated Si substitution or doping effects. The purity of the hard magnetic ThMn₁₂ phase in the bulk magnet reached higher than 97 wt.%. The remanent magnetization and maximum energy product of the prepared Sm(Fe_0.8Co_0.2)₁₁Ti bulk reached high values of 96.0 emu/g and 12.22 MGOe, respectively, as shown in Fig. 1（a）. To investigate the effect of substituted elements in the ThMn₁₂-type Fe-rich compounds Sm(Fe_0.8Co_0.2)₁₀Si₂ and Sm(Fe_0.8Co_0.2)₁₁Ti+Si_x（x = 0, 0.5, and 1） ribbons were produced using a melt spinning method. The magnetic properties of the Sm(Fe_0.8Co_0.2)₁₀Si₂ ribbons with different melt spinning speeds and the Sm(Fe_0.8Co_0.2)₁₁Ti+Si_x ribbons with melt spinning speed of 39 m/s are shown in Fig. 1（b）. The details of the fabrication procedure, microstructure, and magnetic properties of as mentioned compounds will be discussed.更多还原

【Abstract】 Rare-earth intermetallic compounds of R（Fe,M）₁₂（R = rare earth elements, M = transition metals） with ThMn₁₂ structure have been known to be promising permanent magnetic materials since the 1980s [1]. Recently, increasing demand for R has pushed the industry to seek ways to reduce the R-content in hard magnetic materials. In case, strong magnets with the ThMn₁₂ type of structure received much attention [2]. However, during the several tens of years, the research about ThMn₁₂ magnetic materials was not made a breakthrough, due to the rapid development of Nd₂Fe₁₄B. As a turning point of the ThMn₁₂-type Fe-rich compounds research, ThMn₁₂-type Sm(Fe_1-xCo_x)₁₂ compound films with a saturation magnetization of 1.78 T, an anisotropy field of 12 T, and a Curie temperature of 586 °C, all of which are superior to those for Nd₂Fe₁₄B [3], were successfully produced. However, it still has difficulty in stabilizing the unstable ThMn₁₂ phase in fabricating magnetic powders and bulks. In previous research, the ThMn₁₂ structure is also metastable and partial Fe atoms must be substituted with phase stabilizing element（s）, such as Ti, V, Cr, Mn, Mo, W, Al, and Si, which results in magnetization reduction. So, decreasing magnetization or coercivity with the non-magnetic elements substitution is a new challenge for the ThMn₁₂-type Sm(Fe_1-xCo_x)₁₂ compound research. Therefore, we have developed a new fabrication method to produce a high-density Sm(Fe_0.8Co_0.2)₁₁Ti bulk with high purity and magnetic properties and investigated Si substitution or doping effects. The purity of the hard magnetic ThMn₁₂ phase in the bulk magnet reached higher than 97 wt.%. The remanent magnetization and maximum energy product of the prepared Sm(Fe_0.8Co_0.2)₁₁Ti bulk reached high values of 96.0 emu/g and 12.22 MGOe, respectively, as shown in Fig. 1（a）. To investigate the effect of substituted elements in the ThMn₁₂-type Fe-rich compounds Sm(Fe_0.8Co_0.2)₁₀Si₂ and Sm(Fe_0.8Co_0.2)₁₁Ti+Si_x（x = 0, 0.5, and 1） ribbons were produced using a melt spinning method. The magnetic properties of the Sm(Fe_0.8Co_0.2)₁₀Si₂ ribbons with different melt spinning speeds and the Sm(Fe_0.8Co_0.2)₁₁Ti+Si_x ribbons with melt spinning speed of 39 m/s are shown in Fig. 1（b）. The details of the fabrication procedure, microstructure, and magnetic properties of as mentioned compounds will be discussed.更多还原