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Investigation on Local Electron-Spin-Polarization in Nano-Structured Magnetic Thin Films in Equilibrium andNon-Equiibrium States

平衡态和非平衡态纳米结构磁性薄膜中局域电子自旋极化的研究

基本信息

批准号：
17340108
负责人：
MIBU Ko
金额：
$ 10.62万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Nuclear resonant scattering, a newly developing experimental method which can detect magnetic hyperfine field, was applied in order to study local electron-spin-polarization or local magnetism in nano-structured metallic thin films. X-ray beams corresponding to the Mossbauer transition energy of "Fe or rrsSn were monochromatized into a width of several meV and injected to the samples containing "Fe or rrsSn as nuclear probes. The X-rays resonantly scattered by the probing nuclei were recorded as a function of time to obtain "time spectra".After some optimization of the experimental setup, time spectra in good S/N ratio were successfully obtained for a monatomic "Fe layer deposited on a Cr layer. It was found that the time spectra were different among samples with different Cr layer thickness and also between samples with and without a ferromagnetic ssFe layer under the Cr layer. The results suggest that the magnetic structure of the Cr layer and also the magnetic hyperfine field at the "Fe probes are changed by the existence of the underlaid ferromagnetic ssFe layer due to the magnetic frustration effect at the ssFe/Cr interface.Measurements were also done for L2i-type XiYZ Heuslar alloy films and B2-type XY artificial alloy films, which were prepared by alternate deposition of monatomic or sub-atomic layers of ingredient elements. For CosMnSn Heuslar alloy films, beautiful periodic beat patterns were observed in the time spectra, which reflects the realization of samples with highly-ordered crystallographic structures. For CoSn artificial alloys, the hyperfine field was found to be small at both room temperature and low temperatures.In this way, the nuclear resonant scattering offers us some unique information on local magnetism which cannot be obtained by other experimental methods, and would also be applicable to the studies on ltral electron-spin-polarization in non-equilibrium states.

核共振散射是近年来发展起来的一种探测超精细磁场的实验方法，用于研究纳米结构金属薄膜中的局域电子自旋极化或局域磁性。将对应于“Fe”或“rrsSn”穆斯堡尔跃迁能的X射线束单色化为几meV的宽度，并注入到含有“Fe”或“rrsSn”的样品中作为核探针。通过对实验装置的优化，成功地获得了Cr层上沉积单原子Fe层的时间谱。结果发现，不同的Cr层厚度的样品之间的时间谱是不同的，也有和没有铁磁性ssFe层的Cr层下的样品之间。结果表明，由于ssFe/Cr界面处的磁阻挫效应，底层铁磁ssFe层的存在改变了Cr层的磁结构，从而改变了“Fe”探针处的磁超精细场。其通过成分元素的单原子或亚原子层的交替沉积来制备。对于CosMnSn Heuslar合金薄膜，在时间谱中观察到美丽的周期性拍频图案，这反映了具有高度有序晶体结构的样品的实现。对于CoSn人工合金，无论在室温还是低温下，超精细场都很小，这为我们提供了一些用其他实验方法无法获得的局域磁性信息，也适用于非平衡态电子自旋极化的研究.