Abstract
The development of long-range ferromagnetic (FM) order in dilute magnetic topological insulators can induce dissipationless electronic surface transport via the quantum anomalous Hall effect. We measure the magnetic excitations in a prototypical magnetic topological crystalline insulator, Sn0.95Mn0.05Te, using inelastic neutron scattering. Neutron diffraction and magnetization data indicate that our Sn0.95Mn0.05Te sample has no FM long-range order above a temperature of 2 K. However, we observe slow, collective FM fluctuations (<70μeV), indicating proximity to FM order. We also find a series of sharp peaks originating from local excitations of antiferromagnetically (AF) coupled and isolated Mn-Mn dimers with JAF=460μeV. The simultaneous presence of collective and localized components in the magnetic spectra highlight different roles for substituted Mn ions, with competition between FM order and the formation of AF-coupled Mn-Mn dimers.
| Original language | English |
|---|---|
| Article number | 140406 |
| Journal | Physical Review B |
| Volume | 101 |
| Issue number | 14 |
| DOIs | |
| State | Published - Apr 1 2020 |
Funding
Work at the Ames Laboratory was supported by the U.S. Department of Energy (USDOE), Basic Energy Sciences, Division of Materials Sciences and Engineering. Ames Laboratory is operated for the USDOE by Iowa State University under Contract No. DE-AC02-07CH11358. A portion of this research used resources at the Spallation Neutron Source, a USDOE Office of Science User Facility operated by Oak Ridge National Laboratory.