1993 Fiscal Year Final Research Report Summary
Study of High Bit Density Accumulation of Vertical Vloch Lines in a Ferromagnetic Garnet Thin Film
| Project/Area Number |
03650328
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
電子機器工学
|
|---|
| Research Institution | Kyusyu University |
|---|
Principal Investigator |
ADADA Hironori Kyusyu University, Faculty of Engineering, Research Associate, 工学部, 助手 (70201887)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MATSUYAMA Kimihide Kyusyu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (80165919)
|
|---|
| Project Period (FY) |
1991 – 1993
|
| Keywords | Magnetic Memory / Bloch Line Memory / Vcrtical Bloch Linc / Domain Wall / Bubble Domain |
|---|
| Research Abstract |
Wall dynamics on a 1 mum bubble material and chip organization have been studied by both the experiments and simulations for realizing the ultra high bit density Bloch line memory.
1.Wall dynamics and stability of vertical Bloch line (VBL) pair for pulsed bias fields have been investigated and clarified by the experiments for a 1mum bubble martial. The successive VBL write operation were performed and VBL pairs were confirmed to be accumulated in the domain. The dynamic bubble collapse field was measured by increasing the bias field under applying the successive pulsed bias fields. From the comparison this fields with the simulation, the detection of small number of VBL pairs included in the domain has become possible, which was difficult in the measurement of the static one.
2.Study of suitable chip organization for high bit density memory device ;
(1)We have obtained the wide bias field margin of stripe stabilization and performed gate oprations experimentally on the chip with the domain pattern, which were written in an amorphous magnetic film by a focused laser beam scanning system. Bit-by -bit propagation of VBLs was confirmed by the simulation for the chip with the optimized fish-bone shape domain pattern, which can perform both stripe stabilization and bit confinement.
(2)A new bit confinement method utilizing the self-induced periodic stripe structure in permalloy films has been proposed. We have presented the numerical technique for calculating the stripe structure and evaluated the magnetostatic interaction between this structure and VBL pair. We confirmed that the critical anisotropy field, above which the stripe structure develops, is decreased with increasing the film thickness and clarified that the structure period is mainly depended upon the film thickness.
3.Wall and VBL coercivity arising from the spatial nonuniformity in the uniaxial anisotropy and exchange constant was evaluated by using micromagnetic simulation.
|
