Abstract
We report a systematic study of ferromagnetic domains in both single-crystal and thin-film specimens of magnetic topological insulators Cr doped (Bi0.1Sb0.9)2Te3 using magnetic force microscopy (MFM). The temperature and field dependences of MFM and in situ resistance data are consistent with previous bulk transport and magnetic characterization. Bubble-like ferromagnetic domains were observed in both single crystals and thin films. Significantly, smaller domain size (∼500 nm) with narrower domain wall (∼150 − 300 nm) was observed in thin films of magnetic topological insulators, likely due to vertical confinement effect. These results suggest that thin films are more promising for visualization of chiral edge states.
Highlights
We report a systematic study of ferromagnetic domains in both single-crystal and thin-film specimens of magnetic topological insulators Cr doped (Bi0.1Sb0.9)2Te3 using magnetic force microscopy (MFM)
Breaking time reversal symmetries in a topological insulator can lead to exotic quantum phenomena including image magnetic monopoles,[6] giant magneto-optical effects,[7] quantum anomalous hall effect (QAHE),[8] and so on
Ferromagnetic behaviors have been observed in various magnetic Topological insulators (TI), such as Mn doped Bi2Te3,9 Cr and V doped Sb2Te3,10–12 and Cr doped Bi2Se3.13 QAHE was experimentally confirmed in Cr doped BixSb2−xTe3 thin films, which completes the quantum hall effect trio.[14,15,16,17]
Summary
We report a systematic study of ferromagnetic domains in both single-crystal and thin-film specimens of magnetic topological insulators Cr doped (Bi0.1Sb0.9)2Te3 using magnetic force microscopy (MFM).
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