Tuning the dynamic exchange interaction in ferromagnet/semiconductor heterostructures

Yu-Sheng Ou; Yi-Hsin Chiu; N. J. Harmon; Patrick Odenthal; Matthew Sheffield; Michael Chilcote; R. K. Kawakami; M. E. Flatté; E. Johnston-Halperin

doi:10.1117/12.2188800

8 September 2015 Tuning the dynamic exchange interaction in ferromagnet/semiconductor heterostructures

Yu-Sheng Ou, Yi-Hsin Chiu, N. J. Harmon, Patrick Odenthal, Matthew Sheffield, Michael Chilcote, R. K. Kawakami, M. E. Flatté, E. Johnston-Halperin

Author Affiliations +

Proceedings Volume 9551, Spintronics VIII; 95510E (2015) https://doi.org/10.1117/12.2188800
Event: SPIE Nanoscience + Engineering, 2015, San Diego, California, United States

Abstract

We investigate the impact of tunnel barrier thickness on electron spin dynamics in Fe/MgO/GaAs heterostructures using spin-resolved optical pump-probe spectroscopy. Comparison of the Larmor frequency between thick and thin MgO barriers reveals a four-fold variation in exchange coupling strength, and investigation of the inhomogeneous dephasing time, T₂^*, argues that inhomogeneity in the local effective hyperfine field dominates free-carrier spin relaxation across the entire range of barrier thickness. These results provide additional evidence to support the theory of hyperfine-dominated spin relaxation in GaAs at low temperature and in the presence of an externally applied magnetic field. Further, this work lays the foundation for engineering both the exchange coupling and the free carrier spin dynamics in ferromagnet/semiconductor heterostructures, allowing for the exploration of dissipation and transport in the regime of dynamically-driven spin pumping.

Citation Download Citation

Yu-Sheng Ou, Yi-Hsin Chiu, N. J. Harmon, Patrick Odenthal, Matthew Sheffield, Michael Chilcote, R. K. Kawakami, M. E. Flatté, and E. Johnston-Halperin "Tuning the dynamic exchange interaction in ferromagnet/semiconductor heterostructures", Proc. SPIE 9551, Spintronics VIII, 95510E (8 September 2015); https://doi.org/10.1117/12.2188800

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