The Role of Interactions in Systems of Single Domain Ferrimagnetic Iron Oxide Nanoparticles
The Role of Interactions in Systems of Single Domain Ferrimagnetic Iron Oxide Nanoparticles
复制标题
相互作用在单畴亚铁磁性氧化铁纳米粒子系统中的作用
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
R. Hergt
中科院分区：
文献类型：
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作者：
S. Dutz;R. Hergt
磁性纳米颗粒是一种有趣的材料，用于许多医疗和技术应用。一个较少实验研究的问题是由于单个颗粒之间的磁相互作用，颗粒堆积密度对磁性能的影响。为此，通过激光沉积法制备的铁氧化物磁性纳米颗粒作为细干粉，研究了它们的结构和磁性能作为堆积密度的函数。颗粒是在磁性单畴尺寸范围内的近球形单晶，平均直径为21 nm，偶尔表现出尖晶石生长小面。这些颗粒的粉末被分散的氧化硅颗粒稀释，其体积浓度范围为磁铁矿堆积密度的0.2%至68%。剩磁、矫顽力和磁滞损耗的浓度依赖性是通过测量振动样品磁强计中的小回线来确定的。在目前的理论模型的框架中讨论的结果可以理解的磁铁矿的立方各向异性扭曲的一个小的单轴形状的贡献。
Magnetic nanoparticles are interesting materials for a lot of medical and technical applications. A less experimentally investigated question is the influence of particle packing density on magnetic properties due to magnetic interactions between single particles. For this, magnetic nanoparticles of iron oxides prepared as fine dry powder by laser deposition are investigated with respect to their structural and magnetic properties as function of packing density. The particles are nearly spherically shaped single crystals in the magnetic single domain size range with a mean diameter of 21 nm occasionally exhibiting spinel growth facets. Powders of these particles are diluted by nonmagnetic silicon oxide particles in a range of volume concentrations from 0.2 % up to 68 % of the bulk density of magnetite. The concentration dependence of remanence, coercivity and hysteresis losses is determined by measurements of minor loops in a vibrating sample magnetometer. Results which are discussed in the frame of present theoretical models may be understood in terms of the cubic anisotropy of magnetite distorted by a small uniaxial shape contribution.