2004 Fiscal Year Final Research Report Summary
Nanostructure physics in copper oxides-the relation with unconventional properties of high-temperature superconductors and application of new properties
| Project/Area Number |
15510093
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Nanostructural science
|
|---|
| Research Institution | Saga University |
|---|
Principal Investigator |
ZHENG Xu-guang Saga University, Department of Physics, Associate professor, 理工学部, 助教授 (40236063)
|
|---|
| Project Period (FY) |
2003 – 2004
|
| Keywords | nanophysics / charge-stripe / charge order / antiferromagnetism / spin glass / geometric frustration / natural cuprates |
|---|
| Research Abstract |
Main results :
1.We doped holes into the simplest copper oxide of CuO. We have found that the suppression of antiferromagnetism in CuO is dramatically rapid. Moreover, charge-stripe-like order has been observed. We have also obtained evidences of the separation of magnetic phase which suggests charge-stripe-associated spin order from μSR study. We therefore clarified that the charge-stripe, which is considered a key property for the high-temperature superconductors, develops in the simplest compound of CuO.
2.We prepared nanoparticles of CuO and investigated the change in magnetism. We have found that the magnetic transition temperature in nanoparticle CuO is drastically reduced, demonstrating a dramatic finite-size effect. This is the first report of direct evidence of a drastic decrease of the magnetic transition temperature in antiferromagnetic system.
3.We have found spin-glass properties in natural cuprates of Cu_2Cl(OH)_3. Furthermore, we have found that it is a new geometrically frustrated system with d-electron spins. We found the co-existence of spin fluctuation and magnetic order. This discovery uncovers a new route for the study of geometric frustration both in the material aspect as well as in the magnetism (of d-electron spins). As a material route, it provides a new system of M_2X(OH)_3 with a huge number where M is transition metal and X halogen.
These discoveries are partly reflected in 15 papers published or accepted for publication in scientific magazines such as Physical Review Letters.
|
