2004 Fiscal Year Final Research Report Summary
Realization of perpendicular anisotropy by controlling the interaction between magnetic particles in nanocomposite films
| Project/Area Number |
15560572
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Physical properties of metals
|
|---|
| Research Institution | Tokyo Institute of Technology |
|---|
Principal Investigator |
SHI Ji Tokyo Institute of technology, Department of Metallurgy and Ceramics Science, Associate Professor, 理工学研究科, 助教授 (70293123)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Yoshio Tokyo Institute of technology, Department of Metallurgy and Ceramics Science, Professor, 理工学研究科, 教授 (00164351)
|
|---|
| Project Period (FY) |
2003 – 2004
|
| Keywords | perpendicular magnetic anis / nanocomposite / Co-TiN / shape anisotropy / nanofiber microstructure / interface restriction / layered structure / CoPt / AlN |
|---|
| Research Abstract |
Co-TiN nanocomposite films have been fabricated by reactive sputtering of Co and Ti in Ar and N atmosphere, and followed by thermal annealing in a vacuum. The effect of Ti content, Pt addition, and annealing temperature on the microstructure and magnetic properties were investigated in this work. It is found that the as deposited films hardly show ferromagnetic performance. After thermal annealing at appropriate temperatures, the Co-TiN films show ferromagnetic performance, and perpendicular magnetic anisotropy. As to the Ti content, it is found that optimum perpendicular anisotropy is obtained when the mole ratio of Co to Ti is 1:2. And the optimum annealing temperature of such films is 800 C. The occurrence of the perpendicular magnetic anisotropy, we consider, is due to the unique microstructure of such films. The as-deposited films are amorphous with columnar structure. During thermal annealing, Co particles precipitate inside the columns. The particles are close with each other in the direction perpendicular to the substrate surface. But in the in-plane directions these particles are separated by TiN. That means the interaction between Co particles in the perpendicular direction is strong and that in the in-plane directions is relatively weak. Thus the film can be easily magnetized in the perpendicular direction, and perpendicular magnetic anisotropy is induced.
In this work, the magnetic properties of CoPt/AlN layered-structure, especially the magnetic anisotropy, were also studied. It is found that tensile stress can be introduced to the metal layers by inter facial restriction, after thermal annealing of the films, and for this reason, perpendicular magnetic anisotropy can be induced for such a layered structure.
|
