| Project/Area Number |
16360147
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Electronic materials/Electric materials
|
|---|
| Research Institution | Utsunomiya University |
|---|
Principal Investigator |
IRIE Akinobu Utsunomiya Univ., Engineering, Associate professor, 工学部, 助教授 (90241843)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OYA Gin-ichiro Utsunomiya Univ., Engineering, Professor, 工学部, 教授 (00006280)
KITAMURA Michihide Utsunomiya Univ., Engineering, Associate professor, 工学部, 助教授 (90161497)
ISHII Kiyoshi Utsunomiya Univ., Engineering, Professor, 工学部, 教授 (30134258)
|
|---|
| Project Period (FY) |
2004 – 2006
|
| Project Status |
Completed (Fiscal Year 2006)
|
| Budget Amount *help |
¥15,100,000 (Direct Cost: ¥15,100,000)
Fiscal Year 2006: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2005: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2004: ¥11,300,000 (Direct Cost: ¥11,300,000)
|
|---|
| Keywords | high Te superconductor / intrinsic Josephson junctions / mesoscopic phenomena / vortex flow / SQUID / magnet / superconductor structure / spin injection / Bi_2Sr_2CaCu_2O_y / vortex flow / 超伝導ギャップ / 超伝導体接合 / サブミクロン / 帯電効果 / 熱活性モデル |
|---|
| Research Abstract |
We studied quantum tunneling phenomena in intrinsic Josephson superlattice of (Bil-xPbx)_2Sr_2CaCu_2O_y single crystals. In this study, we obtained the following results.
1. We developed the new fabricated process to make a stack of small intrinsic Josephson junctions. By using this process, samples with lateral dimensions ranging from sub-μm^2 to several tens μm^2 were successfully fabricated.
2. The current-voltage characteristics of BPSCCO intrinsic Josephson junctions showed clear multiple branches with high hysteresis and a well-defined gap structure without negative resistance. The quasiparticle I-V characteristics were in agreement with the feature of a weighted, momentum-averaged d-wave model.
3. At intermediate temperature the switching mechanism from zero voltage state to a finite voltage state is due to thermal activation process. At lower temperature switching current distribution became wider due to the influence of multiple switching modes.
4. To analyze the vortex dynamics, the inductive coupling model taking into account thermal fluctuations was proposed. The model reproduced the previous experimental results and suggests that the out-of-phase flow of vortices is stable rather than the in-phase flow, and the oscillations of the vortex flow resistance are not directly related to the structure of the vortex lattice.
5. The dc SQUIDs with in-plane loop geometry and two stacks of intrinsic Josephson junctions were successfully fabricated using the developed process. The fabricated SQUID showed clear periodic and symmetric flux-voltage characteristics due to the quantum interference between the stacks.
6. The hybrid Fe/BSCCO structure was fabricated. After an application of a magnetic field, the suppression of the critical current of intrinsic Josephson junctions due to the spin injection was observed.
|
