Magnetically textured γ-Fe2O3 nanoparticles in a silica gel matrix:: Structural and magnetic properties
Magnetically textured γ-Fe2O3 nanoparticles in a silica gel matrix:: Structural and magnetic properties
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DOI：
10.1063/1.367952
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发表时间：
1998-06-15
影响因子：
3.2
通讯作者：
Boilot, JP
中科院分区：
文献类型：
--
作者：
Bentivegna, F;Ferre, J;Boilot, JP
本文致力于各向异性γ-Fe 2 O3超顺磁性颗粒分散在透明干凝胶基质的磁性和结构特性。利用交变梯度力磁法和一阶、二阶磁光效应研究了凝固过程中施加的磁场对基体内磁场磁化过程的影响。磁化曲线的变化，相对于在相同的颗粒浓度的铁磁流体溶液解释现有的统计方法的基础上扩展到系统的粒度分布，这必须考虑到真实的样品。一个非常好的实验和理论之间的协议实现了对数正态分布的直径，以及类似的推断，从电子显微镜观察在不同的成像模式。该结构分析说明了计算中使用的参数值，并确认了所研究样本模型的基本假设的相关性。实验结果和相关的理论讨论对理解其他磁织构超顺磁系统的磁性质具有一定的参考价值。(C)1998年美国物理学会。
This paper is devoted to magnetic and structural properties of anisotropic gamma-Fe2O3 superparamagnetic particles dispersed in a transparent xerogel matrix. The effect of frozen anisotropy axes and magnetic texture, induced by a magnetic field applied during the solidification of the matrix on the in-field magnetization process, is studied by alternating gradient force magnetometry and first and second order magneto-optical effects. The changes of magnetization curves with respect to the ferrofluid solution at the same particle concentration are interpreted on the basis of an existing statistical approach extended to systems with particle size distribution, which has to be taken into account for real samples. A very good agreement between the experiment and theory was achieved for a log-normal distribution of diameters which well resembles that deduced from electron microscopy observations in different imaging modes. This structural analysis states the parameter values used in calculations and confirms the relevance of basic assumptions of the model for the specimens studied. The experimental results and the related theoretical discussion should be of use to understand magnetic properties of other magnetically textured superparamagnetic systems. (C) 1998 American Institute of Physics.