POLARIZED NEUTRON STUDY OF THE MAGNETIZATION DENSITY DISTRIBUTION WITHIN A COFE2O4 COLLOIDAL PARTICLE .2.
POLARIZED NEUTRON STUDY OF THE MAGNETIZATION DENSITY DISTRIBUTION WITHIN A COFE2O4 COLLOIDAL PARTICLE .2.
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DOI：
10.1016/0304-8853(94)01627-5
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发表时间：
1995-03-01
影响因子：
2.7
通讯作者：
BERKOWITZ, AE
中科院分区：
文献类型：
--
作者：
LIN, D;NUNES, AC;BERKOWITZ, AE
我们分析了涂有油酸和未涂敷的细碎 CoFe2O4 颗粒的 X 射线和偏振中子粉末衍射数据。颗粒的特征在于对数正态尺寸分布。使用假设磁性非相互作用的超顺磁性颗粒、X 射线衍生的颗粒尺寸分布以及磁性无序表面层的存在的模型，我们能够预测观察到的涂覆颗粒的偏振中子 (4,0,0) 粉末衍射剖面。最佳配合需要大约 12 埃厚的异常磁壳。未涂覆颗粒的样品很复杂，显示出可能由烧结引起的铁磁行为的迹象。
We analyzed X-ray and polarized neutron powder diffraction data of finely divided CoFe2O4 particles coated with oleic acid and uncoated. The particles are characterized by a lognormal size distribution. Using a model assuming magnetically noninteracting superparamagnetic particles, X-ray derived particle size distributions, and the existence of a magnetically disordered surface layer, we are able to predict the observed polarized neutron (4,0,0) powder diffraction profiles of the coated particles. The best fit requires a magnetically anomalous shell approximately 12 Angstrom thick. The sample of uncoated particles is complicated, showing signs of ferromagnetic behavior possibly resulting from sintering.