Abstract
The ferromagnetic semiconductor Ba2NiOsO6 (Tmag∼100K) was synthesized at 6 GPa and 1500 °C. It crystallizes into a double perovskite structure [Fm-3m; a=8.0428(1)Å], where the Ni2+ and Os6+ ions are perfectly ordered at the perovskite B site. We show that the spin-orbit coupling of Os6+ plays an essential role in opening the charge gap. The magnetic state was investigated by density functional theory calculations and powder neutron diffraction. The latter revealed a collinear ferromagnetic order in a >21kOe magnetic field at 5 K. The ferromagnetic gapped state is fundamentally different from that of known dilute magnetic semiconductors such as (Ga,Mn)As and (Cd,Mn)Te (Tmag<180K), the spin-gapless semiconductor Mn2CoAl (Tmag∼720K), and the ferromagnetic insulators EuO (Tmag∼70K) and Bi3Cr3O11 (Tmag∼220K). It is also qualitatively different from known ferrimagnetic insulators and semiconductors, which are characterized by an antiparallel spin arrangement. Our finding of the ferromagnetic semiconductivity of Ba2NiOsO6 should increase interest in the platinum group oxides, because this alternative class of materials should be useful in the development of spintronic, quantum magnetic, and related devices.
Original language | English |
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Article number | 235158 |
Journal | Physical Review B |
Issue number | 23 |
DOIs | |
State | Published - Dec 28 2016 |
Funding
The XAS measurements were supported by Chin-Wen Pao. M.P.G thanks the Alexander von Humboldt Foundation for financial support through the Georg Forster Research Fellowship Program. M.P.G. thanks K. Koepernik and R. Laskowski for helpful discussion, and M.R. thanks M. Knupfer, U. Rler, and H. Rosner for helpful discussion. M.P.G. and M.R. thank U. Nitzsche for technical assistance. This research was supported in part by the World Premier International Research Center of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan and the Japan Society for the Promotion of Science (JSPS) through a Grant-in-Aid for Scientific Research (Grants No. 25289233, No. 15K14133, and No. 16H04501). The research conducted at ORNL's High Flux Isotope Reactor was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy.