( 1. 兰州大学 磁学与磁性材料教育部重点实验室，兰州 730000;
2. 兰州大学 材料科学与工程系， 兰州 730000)
摘 要: 采用液相还原法， 通过控制颗粒不同晶面的生长速率， 制备了不同尺寸、 不同Fe含量的片状FexCo1-x(x=0.1~0.6) 合金纳米颗粒， 研究了不同成分铁钴合金纳米颗粒的微结构及形状对其磁性的影响。 结果表明， 当x=0.1时， 铁钴合金纳米片为面心立方和密堆六方两相共存结构； 当x≥0.2时， 铁钴合金纳米片为单相体心立方结构。 同块体合金相比， 铁钴合金纳米片的点阵发生膨胀。 纳米片的饱和磁化强度低于合金相应的块体值， 纳米片的矫顽力高于块体及球形纳米颗粒的矫顽力, 并且随铁含量的提高而降低。 颗粒的片状形貌使得一致取向Fe0.6Co0.4合金纳米片的磁化行为随外场方向而改变， 磁化的易轴在面内方向， 难轴为纳米片的法线方向。
关键字: 铁钴合金； 片状纳米颗粒； 微结构； 磁性
（ 1. Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China;
2. Department of Materials Science and Engineering, Lanzhou University,
Lanzhou 730000, China）
Abstract: The nanoplatelets of FexCo1-x (x=0.1-0.6) alloy were prepared through reduction reaction by controlling the growing rates of different crystallographic planes. The synthesized alloy nanoplatelets with different compositions are plate-like in shape. The influence of microstructure and shape of nanoplatelets on their magnetic properties were studied. The results show that the nanoplatelet consists of FCC phase and HCP phase when the Fe content is 10%. But when the Fe content is equal to and more than 20%, the alloy has single-phased BCC structure. The lattice constants of the alloy nanoplatelets are larger than the corresponding values of bulk material and increase with increasing Fe content. The alloy nanoplatelets are all ferromagnetic and their saturated magnetizations are slightly lower than the corresponding values of bulk material. The coercivities are larger than those of the corresponding bulk material and the spherical nanoparticles, and decrease with the increase of Fe content. Magnetic hysteresis loops of the disk along different directions deviating from the nanoplatelets plane are obviously different, indicating that the easy-axis is in the in-plane direction and the hard-axis is vertical to the in-plane direction.
Key words: Fe-Co alloy; nanoplatelet; microstructure; magnetic property
