Surface spin freezing of ferrite nanoparticles evidenced by magnetization measurements
Surface spin freezing of ferrite nanoparticles evidenced by magnetization measurements
复制标题
DOI：
10.1063/1.2163844
复制
发表时间：
2006-04-15
影响因子：
3.2
通讯作者：
Goya, G. F.
中科院分区：
文献类型：
--
作者：
Alves, C. R.;Aquino, R.;Goya, G. F.
对平均尺寸为3.5 ~ 10.4 nm的铁氧体铜纳米颗粒进行了磁化和场内穆斯堡尔测量。我们的结果表明，纳米颗粒是具有磁性无序表面壳的良好结晶的单畴。在低温下，除了通常的修正布洛赫行为外，还观察到最小颗粒的饱和磁化强度急剧增加。磁化曲线的这种跳跃似乎与表面自旋在45 K以下冻结有关。(C) 2006年美国物理研究所。
Magnetization and in-field Mossbauer measurements were performed on copper ferrite nanoparticles with average sizes ranging from 3.5 to 10.4 nm. Our results show that the nanoparticles are well-crystallized single domains with a magnetically disordered surface shell. A sharp increase in the saturation magnetization at low temperatures, in addition to the usual modified Bloch behavior, was observed for the smallest particles. This jump in magnetization curves seems to be related to the freezing of the surface spins below a temperature of about 45 K. (C) 2006 American Institute of Physics.