Study on spin structures and electron-lattice interaction of nanomaterials using nuclear resonant scattering.

利用核共振散射研究纳米材料的自旋结构和电子晶格相互作用。

基本信息

批准号：
15540308
负责人：
SETO Makoto
金额：
$ 2.11万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Nanostructured materials like quantum wires have attracted much interest for their novel properties and the possibilities for new devices. It is well known that nanostructured materials show different electric and thermodynamical properties as compared to ordinary macroscopic materials. For the further understanding and new applications, microscopic studies on nanosized materials are indispensable.We have measured the time and energy spectra of nuclear resonant scattering of synchrotron radiation from magnetic Fe nanowires to investigate the electronic states and lattice dynamics of the Fe nanowires, As for the electronic states, we studied the correlation between the spin structure and the shape of the wires. From the measured time spectra of the Fe nanowires, the value of internal magnetic field is obtained to be 32.9 T. This agrees with the value of the bulk Fe (33 T), and this result indicates the electronic state of Fe atoms in our nanowire sample is almost the same as that of Fe atoms in a bulk sample. Furthermore, it was confirmed that the direction of the magnetic field is anisotropic and coincides with the direction of the nanowires. Our results show that this method is useful for the study of electronic states of nanomaterilas. As for the vibrational states, we studied the difference between the bulk state and the nanowires. Because it is possible to obtain the information on the specific elements by using nuclear resonant scattering, we can obtain the intrinsic lattice dynamics of nanoweires without the vibration of the substrate material. The observed phonon spectra show the dependence on the size of the samples, and we concluded it is due to the anharmonic effect.

量子线等纳米结构材料因其新颖的特性和新设备的可能性而引起了人们的广泛兴趣。众所周知，与普通宏观材料相比，纳米结构材料表现出不同的电学和热力学性质。为了进一步理解和新的应用，对纳米材料的微观研究是必不可少的。我们测量了磁性铁纳米线同步辐射的核共振散射的时间和能谱，以研究铁纳米线的电子态和晶格动力学，在电子态中，我们研究了自旋结构和导线形状之间的相关性。从 Fe 纳米线的测量时间谱中，得到内部磁场值为 32.9 T。这与块体 Fe 的值 (33 T) 一致，这个结果表明了我们的纳米线中 Fe 原子的电子状态样品中的 Fe 原子几乎与块状样品中的 Fe 原子相同。此外，还证实磁场的方向是各向异性的并且与纳米线的方向一致。我们的结果表明该方法对于纳米材料电子态的研究很有用。至于振动态，我们研究了体态和纳米线之间的差异。由于利用核共振散射可以获得特定元素的信息，因此我们可以在不振动基底材料的情况下获得纳米线的固有晶格动力学。观察到的声子光谱显示出对样品尺寸的依赖性，我们得出结论这是由于非简谐效应。