| Project/Area Number |
20310078
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Microdevices/Nanodevices
|
|---|
| Research Institution | Kyushu University |
|---|
Principal Investigator |
YOSHITAKE Tsuyoshi Kyushu University, 総合理工学研究院, 准教授 (40284541)
|
|---|
| Project Period (FY) |
2008 – 2010
|
| Project Status |
Completed (Fiscal Year 2010)
|
| Budget Amount *help |
¥19,890,000 (Direct Cost: ¥15,300,000、Indirect Cost: ¥4,590,000)
Fiscal Year 2010: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Fiscal Year 2009: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2008: ¥15,080,000 (Direct Cost: ¥11,600,000、Indirect Cost: ¥3,480,000)
|
|---|
| Keywords | 量子効果 / ヘテロ超格子 / 層間結合 / Fe-Si / 人工格子 / スピントロニクス / 磁気層間結合 / 交換結合 / 磁気抵抗効果 / 電流注入 |
|---|
| Research Abstract |
Spin-dependent phenomena have recently received much attention. Particularly, interlayer couplings between ferromagnetic layers separated by nonmagnetic metal and insulator spacer layers have been investigated to a large extent since they can induce the spin-dependent scattering of conduction carriers and spin-dependent tunneling, which are exploited for achieving the giant magnetoresistance (GMR) and tunnel magnetoresistance (TMR) effects, respectively. At present, the switching of interlayer couplings is made by applied magnetic fields. In this study, in order to switch them by the other methods such as light irradiation, thermal heating, and current injection, semiconducting interlayers were employed. Actually ferromagnetic Fe_3Si/semiconducting FeSi_2 superlattices were prepared by sputtering and interlayer couplings were attempted to be switched by their methods. Although current in plane (CIP) films exhibited a change in the electrical resistivity for irradiation with a 1.3-μm la
… More
ser, which was expected to be due to a change in the interlayer coupling from antiferromagnetic (AF) to ferromagnetic (F) coupling, the change in the electrical resistivity was extremely small to be detected. Thus, we adapted current perpendicular plane (CPP) geometry for the detection. Owing to that, the magnetoresistance ratio was enhanced to be approximately 10%. This value is an order of magnitude larger than that of the CIP films. The CPP films exhibited hysteresis loops for the injection current. From the change in the hysteresis loop under magnetic field, the origin of the hysteresis loops was expected to be a change in the interlayer coupling. It was confirmed that the interlayer coupling of the CPP films was obviously changed from AF coupling at room temperature to F coupling at temperatures of lower than 100 K. The CPP films also exhibited temperature-dependent interlayer couplings : AF coupling in a direction perpendicular to the plane induced at room temperature gradually weakened with a decrease in temperature and it finally disappeared at low temperatures. Less
|
