| Co-Investigator(Kenkyū-buntansha) |
TERADA Norio Kagoshima University, Graduate School of Science and Engineering, Professor, 大学院・理工学研究科, 教授 (20322323)
OBARA Kozo Kagoshima University, Graduate School of Science and Engineering, Professor, 大学院・理工学研究科, 教授 (10094129)
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| Research Abstract |
Theoretical results.
To use shape memory alloys (SMA) in wide temperature region, it is important to control the phase transition temperature (PTT). The PTT of ferromagnetic SMA Ni-Mn-Ca-X (X=transition elements) was predicted theoretically on the basis of electronic states. Investigations to control PTT have also been done for TiNi-based alloys by adding the third elements (X atoms). The site preference of X atoms was examined and it was predicts that Fe and Co atoms prefer the Ni site and Cu and Zn atoms the Ti site. The electronic structures of films of Ni_<2.17>Mn_<0.83>Ga, TiNi, TiNi_<8/9>Fe_<1/9> were calculated and the characteristics were clarified.
Experimental results.
In order to make thin films of shape memory alloys by using sputtering processes, we clarified following points; effects of argon gas flow in transfer processes of sputtered particles, control of the thin film composition with very high accuracy by introducing the second attachment probability of sputtered particles and collision process of sputtered particles in surface boundary layer on the rotating substrate. Control of the fine structures in thin films was impossible due to the high energy irradiation from plasma. For developing new nanostructured devices with shape memory alloys, it is very important to decrease the energy of sputtered particles. To evaluate the electron states in half-metallic oxides thin films, spin polarized electron spectroscopy with high accuracy was developed.
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