| Project/Area Number |
14540313
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
固体物性Ⅰ(光物性・半導体・誘電体)
|
|---|
| Research Institution | ANAN NATIONAL COLLEGE OF TECHNOLOGY |
|---|
Principal Investigator |
NAKAMURA Atsunobu Anan National College of Technology, Professor, 一般教科, 教授 (00217829)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NONOYAMA Shinji Yamagata University, Faculty of Education, Associate Professor, 教育学部, 助教授 (50221487)
|
|---|
| Project Period (FY) |
2002 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
|
| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥1,300,000 (Direct Cost: ¥1,300,000)
|
|---|
| Keywords | magnetic wire / domain wall / spin fluctuation / conductance / atomic contact |
|---|
| Research Abstract |
In the nanometer-scale metals, a domain wall(DW) nucleation and dynamics have become the subjects of current interest. Specifically, the negative magnetoresistance effect on the electrical resistivity due to the DW in ferromagnetic wires has been reported by many researchers. Also, exotic nonlinear transports were reported in these metallic wires containing ferromagnetic domain walls.
To elucidate basic features of a ferromagnetic wire with a DW, we calculated the excitation spectrum for the spin fluctuation. In the study, we treated the Heisenberg model with taking the real sample structures into consideration. Then, we presented the method to obtain the Green function for the structure in a framework of the random phase approximation(RPA). It was shown that the low energy excitation is attributed to the DW and the characteristic spin-wave spectrum depends on the existence of the DW and the dimension of leads for the structure.
Next, the effects of the DW and its pinning center on the electron conduction are studied in a framework of the RPA. We show that the DW enhances the resistance due to the spin fluctuation around it. Furthermore, the pinning center plays an important role of suppression of the spin fluctuation, which leads to the reduction of the resistance when the DW locates at the pinning center. It is shown that the results obtained are consistent with the experimental findings.
|
