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

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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.