Effect of annealing on magnetic properties of Ni80Fe20 permalloy nanoparticles prepared by polyol method.
Effect of annealing on magnetic properties of Ni80Fe20 permalloy nanoparticles prepared by polyol method.
复制标题
退火对多元醇法制备Ni80Fe20坡莫合金纳米颗粒磁性能的影响
DOI：
10.1166/jnn.2011.3981
复制
发表时间：
2011
影响因子：
--
通讯作者：
O. Kitakami
中科院分区：
文献类型：
--
作者：
G. Qin;W. Pei;Y. Ren;Y. Shimada;Y. Endo;M. Yamaguchi;S. Okamoto;O. Kitakami
采用多元醇法在180 ℃下处理2 h制备了粒径分布窄、成分均匀的Ni 80 Fe 20坡莫合金纳米颗粒，通过添加适量的K2 PtCl 4试剂，其粒径可在20-440 nm范围内调节。X射线衍射结果表明，NiFe纳米粒子为面心立方结构。K_2PtCl_4的加入不影响NiFe纳米颗粒的组成，但显著减小了颗粒尺寸。所制备的NiFe纳米颗粒的饱和磁化强度和矫顽力均随颗粒尺寸的减小而减小。然而，在280 ℃退火后，不同尺寸的NiFe纳米颗粒的饱和磁化强度急剧增加，并接近于约440 nm NiFe颗粒的体相，最大磁化强度（约270 Oe）发生在约50 nm的临界尺寸处。这些NiFe纳米粒子的磁性依赖于退火已被讨论，考虑到表面化学。
Ni80Fe20 permalloy nanoparticles with narrow size distribution and homogeneous composition have been prepared by the polyol processing at 180 degrees C for 2 h and their particle sizes can be tunable in the size range of 20-440 nm by proper addition of K2PtCI4 agent. X-ray diffraction results show that the NiFe nanoparticles are of face centered cubic structure. The addition of K2PtCl4 does not affect the composition of NiFe NPs but decreases the particle size remarkably. Both saturation magnetization and coercivity of the as-prepared NiFe nanoparticles decrease with decreasing particle size. Annealed at 280 degrees C, however, the saturation magnetization of various sized NiFe nanoparticles increases drastically and approaches to the bulk for the -440 nm NiFe particles, and a maximum coercivity (-270 Oe) happens at a critical size of -50 nm. The magnetic property dependency of these NiFe nanoparticles on annealing has been discussed by considering the surface chemistry.