| 학회 | 한국재료학회 |
| 학술대회 | 2005년 봄 (05/26 ~ 05/27, 무주리조트) |
| 권호 | 11권 1호 |
| 발표분야 | 전자재료 |
| 제목 | Vapor deposition방법으로 성장시킨 비정질 Ge1-xMnx 박막의 자기적 특성 및 자기수송 특성 |
| 초록 | Magnetic properties of amorphous Ge1-xMnx thin films were investigated. The semiconductor thin films were grown at 373K on (100)Si wafers by using a thermal evaporator. Growth rate was ~40nm/min and average film thickness was around 500nm. Thickness and composition were measured by utilizing an alpha-step and an energy dispersive X-ray spectroscopy, respectively. X-ray analysis shows that the Ge1-xMnx thin films are amorphous when Mn concentration is less than 30 at%, but diffraction peaks appeared when Mn concentration exceeds 30at%. The electrical resistivities of Ge1-xMnx thin films are 5.0×10-4~1.1Ωcm at room temperature and decrease with increasing Mn concentration. Magnetic properties of amorphous Ge1-xMnx thin films were measured by using a VSM and a SQUID. The saturation magnetization of amorphous semiconductor thin films vary with Mn concentration, and the largest saturation magnetization is ~100emu/cc for 11.8at% Mn at 5K. Low temperature magnetization characteristics and magnetic hysteresis loops measured at various temperatures show that the amorphous Ge1-xMnx thin films are ferromagnetic at low temperature but the ferromagnetic magnetization are changing gradually into paramagnetic as increasing temperature. The Curie temperature of amorphous Ge1-xMnx thin films is considered to be around 150K. The in-field electrical resistivity of amorphous Ge1-xMnx thin films is lower than the zero-field electrical resistivity when T＜TC, but the reverse is true when T＞TC. However, the in-field electrical resistivity of amorphous Ge1-xMnx thin films is always higher than the zero-field electrical resistivity when Mn concentration is larger than ~12at%. In Addition, magnetotransport characteristics of amorphous Ge1-xMnx thin films show anomalous Hall phenomenon and negative magnetoresistance when T＜TC. The results suggest that the Mn atoms in amorphous Ge1-xMnx thin films be related to spin dependent scattering depending on magnetization. Acknowledgement This work was supported by the Research Center for Advanced Magnetic Materials (RECAMM, Chungnam National University, Korea) and the Brain Korea 21 Program (BK21, the Ministry of Education & Human Resource Development, Korea). |
| 저자 | 유상수1, 찬티난안1, 김익환1, 임영언1, 김도진1, 김효진1, 김창수2, 류현2, 오상준3 |
| 소속 | 1충남대, 2한국표준과학(연), 3한국기초과학지원(연) |
| 키워드 | 묽은 자성반도체; spin injection 소재 |
