Synthesis of Carbon hcp Co fine particle encaged in Carbon nano capsules utilizing laser ablation

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 10650009
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Applied materials science/Crystal engineering
• Research Institution: MIE UNIVERSITY
• Principal Investigator: MASUDA Morio Mie University, Department of Physics Engineering, Professor, 工学部, 教授 (20023137)
• Co-Investigator(Kenkyū-buntansha): FUJIHARA Yuji Mie University, Department of Physics Engineering, Research Associate, 工学部, 助手 (90301225) ; SAITO Yahachi Mie University, Department of Electronics, Associate Professor, 工学部, 助教授 (90144203)
• Project Period (FY): 1998 – 1999
• Keywords: Co / Carbon / nano capsule / laser ablation

Research Abstract

The magnetic properties of Co-C thin films deposited by laser ablation method were investigated. The structures of Co-C thin films were also investigated by X-ray diffractions.
Co-C thin films were deposited onto glass substrates using composite Co-C target (Method 1). We also deposited Co-C thin films with the different geometry that Co and C targets were arranged separately (Method 2). The film thickness was 200Å-1000Å.
Samples from Method 1 included Co fine particle. Saturation magnetization and coercivity were about 1200 emu/cc and 300 Oe. And we confirmed that the hcp Co particles were obtained. However, the average particle size estimated by X-ray diffraction peak was 26nm. We had no decrease the particle size in order to apply the Co-C thin films to magnetic recording media.
In order to decrease the particle size we deposited Co-C films using Method 2 with annealing. As deposited samples had very small saturation magnetization and coercivity. It was indicated that the Co particle is very small. After annealing, saturation magnetization and coercivity increased. But we could not obtain the hcp Co particles. It was very difficult that the control of structure and composition using co-ablation.
We deposited Co/C multilayer in order to control the sample composition strictly. After deposition, we annealed the samples to obtain the Co fine particles. Samples after annealing indicated large saturation magnetization and coercivity, but hcp Co particles were not obtained. We speculate that this is because the annealing temperature is less than the phase transition temperature hcp Co.
In conclusion, we succeeded in control of the composition on Co-C thin films, but hcp Co fine particles were not obtained. We can except that the hcp Co fine particles were obtained with introducing the multilayerd structure and annealing.