title: Coexistence of high-T(c) ferromagnetism and n-type electrical conductivity in FeBi2Se4.
abstract: 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.
authors.affiliation: Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
authors.forename: Kulugammana G S
authors.initials: KG
authors.lastname: Ranmohotti
authors.forename: Honore
authors.initials: H
authors.lastname: Djieutedjeu
authors.forename: Juan
authors.initials: J
authors.lastname: Lopez
authors.forename: Alexander
authors.initials: A
authors.lastname: Page
authors.forename: Neel
authors.initials: N
authors.lastname: Haldolaarachchige
authors.forename: Hang
authors.initials: H
authors.lastname: Chi
authors.forename: Pranati
authors.initials: P
authors.lastname: Sahoo
authors.forename: Ctirad
authors.initials: C
authors.lastname: Uher
authors.forename: David
authors.initials: D
authors.lastname: Young
authors.forename: Pierre F P
authors.initials: PF
authors.lastname: Poudeu