Large surface magnetic contribution in amorphous ferromagnetic nanoparticles
Large surface magnetic contribution in amorphous ferromagnetic nanoparticles
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DOI：
10.1103/physrevb.65.144416
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发表时间：
2002-04-01
影响因子：
3.7
通讯作者：
Romero, H
中科院分区：
文献类型：
--
作者：
De Biasi, E;Ramos, CA;Romero, H
我们测量了类似于3-nm（Fe 0.26 Ni 0.74）（50）B-50铁磁非晶纳米颗粒的磁化强度。我们的研究结果表明，在M（H），M（T）和弛豫测量的磁性的表面贡献的证据。我们观察到随着温度的降低，在M（H）曲线中的非饱和分量，在零场冷却M（T）数据中的两个最大值的存在下，和两个粘度制度的磁化弛豫数据的磁化强度大幅度增加。结果已被解释由一个简单的模型，其中我们认为每个单域粒子作为一个核心加壳系统的单轴各向异性作用于核心和表面各向异性作用于壳。基于该核壳模型的蒙特卡罗模拟定性地再现了所有观察到的现象。
We present magnetization measurements on similar to3-nm (Fe0.26Ni0.74)(50)B-50 ferromagnetic amorphous nanoparticles. Our results show evidence of the surface contribution to the magnetic properties in the M(H), M(T) and relaxation measurements. We observe a large increase in the magnetization with decreasing temperature, a nonsaturated component in the M(H) curves, the presence of two maxima in the zero-field-cooling M(T) data, and two viscosity regimes in magnetization relaxation data. The results have been interpreted by a simple model where we consider each single-domain particle as a core plus shell system with a uniaxial anisotropy acting on the core and a surface anisotropy acting on the shell. Monte Carlo simulations based in this core-shell model qualitatively reproduce all the observed phenomena.