| AVS 54th International Symposium | |
| Magnetic Interfaces and Nanostructures | Thursday Sessions |
| Session MI-ThA |
| Session: | Magnetic Semiconductors II |
| Presenter: | J. Yu, University of Virginia |
| Authors: | J. Yu, University of Virginia J. Lu, University of Virginia K.G. West, University of Virginia L. He, University of Virginia R. Hull, University of Virginia S.A. Wolf, University of Virginia |
| Correspondent: | Click to Email |
Ferromagnetism in Group IV semiconductors produced by transition metal doping is of great interest due to their potential applications in spintronics. In this study, we use ion implantation to introduce Mn ions into Ge. 0.5~4 at. % Mn ion was implanted into 200 nm Ge thin films. Both single implantation and dual implantation were used to prepare samples. The dual ion implantation was performed at 75 °C to improve the uniformity of Mn distribution and avoid formation of a ferromagnetic Mn5Ge3 phase which forms at higher implant temperatures. The implantation damage to Ge was healed by rapid thermal annealing at temperatures ranging from 300 to 800 °C in forming gas. Moment vs. Temperature showed that the ferromagnetic transition temperature was ~ 60 K for 4% samples annealed at 300 °C for 1.5 minutes. The saturation moment at 5K is 0.12 Bohr magnetons per Mn. Transport measurements using the Van der Pauw method were performed to study the correlation between the magnetization and resistivity of Mn:Ge. Significant magnetoresistance and anomalous Hall effect were observed on samples annealed at 300 °C for 1 and 1.5 minutes. The normal and anomalous Hall coefficients are both calculated and confirmed with transport measurement. Cross-section TEM study is underway to determine the phase composition and the distribution of Mn ions in this dual implanted sample annealed at 300°C.