Coexistence of high-Tc ferromagnetism and n-type electrical conductivity in FeBi2Se4
The discovery of n-type ferromagnetic semiconductors (n-FMSs) exhibiting high electrical conductivity and Curie temperature (Tc) above 300 K would dramatically improve semiconductor spintronics and pave the way for the fabrication of spin-based semiconducting devices. However, the realization of high-Tc n-FMSs and p-FMSs in conventional high-symmetry semiconductors has proven extremely difficult due to the strongly coupled and interacting magnetic and semiconducting sublattices. Here we show that decoupling the two functional sublattices in the low-symmetry semiconductor FeBi2Se4 enables unprecedented coexistence of high n-type electrical conduction and ferromagnetism with Tc ≈ 450 K. The structure of FeBi2Se4 consists of well-ordered magnetic sublattices built of [FenSe4n+2]∞ single-chain edge-sharing octahedra, coherently embedded within the three-dimensional Bi-rich semiconducting framework. Magnetotransport data reveal a negative magnetoresistance, indicating spin-polarization of itinerant conducting electrons. These findings demonstrate that decoupling magnetic and semiconducting sublattices allows access to high-Tc n- and p-FMSs as well as helps unveil the mechanism of carrier-mediated ferromagnetism in spintronic materials.
Publication Source (Journal or Book title)
Journal of the American Chemical Society
Ranmohotti, K., Djieutedjeu, H., Lopez, J., Page, A., Haldolaarachchige, N., Chi, H., Sahoo, P., Uher, C., Young, D., & Poudeu, P. (2015). Coexistence of high-Tc ferromagnetism and n-type electrical conductivity in FeBi2Se4. Journal of the American Chemical Society, 137 (2), 691-698. https://doi.org/10.1021/ja5084255