Surface anisotropy, hysteretic, and magnetic properties of magnetite nanoparticles: A simulation study
Surface anisotropy, hysteretic, and magnetic properties of magnetite nanoparticles: A simulation study
复制标题
DOI：
10.1063/1.3148865
复制
发表时间：
2009-06
影响因子：
3.2
通讯作者：
J. Mazo‐Zuluaga;J. Restrepo;F. Muñoz;J. Mejía‐López
中科院分区：
文献类型：
--
作者：
J. Mazo‐Zuluaga;J. Restrepo;F. Muñoz;J. Mejía‐López
在这项研究中，我们解决的作用，表面各向异性的磁滞回线的磁铁矿Fe 3 O 4纳米粒子和情况下产生的水平和垂直位移的磁滞回线的滞后特性。我们的分析涉及温度依赖性和颗粒尺寸效应。考虑了2至7纳米范围内的不同粒度。我们的理论框架是基于一个三维的经典海森堡模型与最近邻相互作用涉及四面体（A）和八面体（B）的铁。立方磁晶各向异性的核心自旋，表面自旋的单离子网站的各向异性，并与均匀的外部磁场的相互作用被认为是。我们的研究结果揭示了低温交换偏置场的开始，它可以是正的或负的，在足够高的值的表面各向异性常数（KS）。磁化率数据，分别计算的核心和表面，表明在硬-软磁性的差异在核心-表面接口。
In this study we address the role of surface anisotropy on the hysteretic properties of magnetite Fe3O4 nanoparticles and the circumstances yielding both horizontal and vertical shifts in the hysteresis loops. Our analysis involves temperature dependence and particle size effects. Different particle sizes ranging from 2 up to 7 nm were considered. Our theoretical framework is based on a three-dimensional classical Heisenberg model with nearest magnetic neighbor interactions involving tetrahedral (A) and octahedral (B) irons. Cubic magnetocrystalline anisotropy for core spins, single-ion site anisotropy for surface spins, and interaction with a uniform external magnetic field were considered. Our results revealed the onset of low temperature exchange bias field, which can be positive or negative at high enough values of the surface anisotropy constant (KS). Susceptibility data, computed separately for the core and the surface, suggest differences in the hard-soft magnetic character at the core-surface inte...