journal article·2016-10-21Open access

Visualizing ferromagnetic domain behavior of magnetic topological insulator thin films

Wenbo Wang, Cui-Zu Chang, Jagadeesh S Moodera, Weida Wu

npj Quantum Materials· Volume 1· Issue 1

Abstract

Abstract A systematic magnetic force microscopy (MFM) study of domain behavior in thin films of the magnetic topological insulator Sb1.89V0.11Te3 reveals that in the virgin domain state, after zero-field cooling, an equal population of up and down domains occurs. Interestingly, the cooling field dependence of MFM images demonstrates that a small cooling magnetic field (approximately 5–10 Oe) is sufficient to significantly polarize the film despite the coercive field (HC) for these films being on the order of a tesla at low temperature. By visualizing the magnetization reversal process around HC of V-doped Sb2Te3, we observed a typical domain behavior of a ferromagnet, i.e., domain nucleation and domain wall propagation. Our results provide direct evidence of ferromagnetic behavior of the magnetic topological insulator, a necessary condition for a robust quantum anomalous Hall effect.
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Research context

OpenAlex topics: Topological Materials and Phenomena · Advanced Condensed Matter Physics · 2D Materials and Applications

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References (33)

Show source-provided references
1. Haldane, F. D. M. Model for a quantum hall effect without landau levels: Condensed-matter realization of the ‘parity anomaly’. Phys. Rev. Lett. 61, 2015–2018 (1988).10.1103/PhysRevLett.61.2015 ↗
2. Onoda, M. & Nagaosa, N. Quantized anomalous Hall effect in two-dimensional ferromagnets: Quantum Hall effect in metals. Phys. Rev. Lett. 90, 206601 (2003).10.1103/PhysRevLett.90.206601 ↗
3. Liu, C. X., Qi, X. L., Dai, X., Fang, Z. & Zhang, S. C. Quantum anomalous Hall effect in Hg1-yMnyTe quantum wells. Phys. Rev. Lett. 101, 146802 (2008).10.1103/PhysRevLett.101.146802 ↗
4. Qiao, Z. et al. Quantum anomalous Hall effect in graphene proximity coupled to an antiferromagnetic insulator. Phys. Rev. Lett. 112, 116404 (2014).10.1103/PhysRevLett.112.116404 ↗
5. Qiao, Z. H. et al. Quantum anomalous Hall effect in graphene from Rashba and exchange effects. Phys. Rev. B 82, 161414 (2010).10.1103/PhysRevB.82.161414 ↗
6. Zhang, H., Lazo, C., Bluegel, S., Heinze, S. & Mokrousov, Y. Electrically tunable quantum anomalous Hall effect in graphene decorated by 5d transition-metal adatoms. Phys. Rev. Lett. 108, 056802 (2012).10.1103/PhysRevLett.108.056802 ↗
7. Ezawa, M. Valley-polarized metals and quantum anomalous Hall effect in silicene. Phys. Rev. Lett. 109, 055502 (2012).10.1103/PhysRevLett.109.055502 ↗
8. Nomura, K. & Nagaosa, N. Surface-quantized anomalous Hall current and the magnetoelectric effect in magnetically disordered topological insulators. Phys. Rev. Lett. 106, 166802 (2011).10.1103/PhysRevLett.106.166802 ↗
9. Yu, R. et al. Quantized anomalous Hall effect in magnetic topological insulators. Science 329, 61–64 (2010).10.1126/science.1187485 ↗
10. Qi, X. L., Hughes, T. L. & Zhang, S. C. Topological field theory of time-reversal invariant insulators. Phys. Rev. B 78, 195424 (2008).10.1103/PhysRevB.78.195424 ↗
11. Hor, Y. S. et al. Development of ferromagnetism in the doped topological insulator Bi2-xMnxTe3 . Phys. Rev. B 81, 195203 (2010).10.1103/PhysRevB.81.195203 ↗
12. Dyck, J. S., Drasar, C., Lost’ak, P. & Uher, C. Low-temperature ferromagnetic properties of the diluted magnetic semiconductor Sb2-xCrxTe3 . Phys. Rev. B 71, 115214 (2005).10.1103/PhysRevB.71.115214 ↗
13. Dyck, J. S., Hajek, P., Losit’ak, P. & Uher, C. Diluted magnetic semiconductors based on Sb2-xVxTe3 (0.01≤x≤0.03). Phys. Rev. B 65, 115212 (2002).10.1103/PhysRevB.65.115212 ↗
14. Zhou, Z., Chien, Y. J. & Uher, C. Thin film dilute ferromagnetic semiconductors Sb2-xCrxTe3 with a Curie temperature up to 190 K. Phys. Rev. B 74, 224418 (2006).10.1103/PhysRevB.74.224418 ↗
15. Haazen, P. P. J. et al. Ferromagnetism in thin-film Cr-doped topological insulator Bi2Se3 . Appl. Phys. Lett. 100, 082404 (2012).10.1063/1.3688043 ↗
16. Li, H. et al. Carriers dependence of the magnetic properties in magnetic topological insulator Sb1.95-xBixCr0.05Te3 . Appl. Phys. Lett. 101, 072406 (2012).10.1063/1.4746404 ↗
17. Wang, W. et al. Visualizing ferromagnetic domains in magnetic topological insulators. APL Mater. 3, 083301 (2015).10.1063/1.4921093 ↗
18. Chang, C. Z. et al. Experimental observation of the quantum anomalous Hall effect in a magnetic topological insulator. Science 340, 167–170 (2013).10.1126/science.1234414 ↗
19. Checkelsky, J. G. et al. Trajectory of the anomalous hall effect towards the quantized state in a ferromagnetic topological insulator. Nat. Phys. 10, 731–736 (2014).10.1038/nphys3053 ↗
20. Kou, X. et al. Scale-invariant quantum anomalous hall effect in magnetic topological insulators beyond the two-dimensional limit. Phys. Rev. Lett. 113, 137201 (2014).10.1103/PhysRevLett.113.137201 ↗
21. Kou, X. et al. Metal-to-insulator switching in quantum anomalous Hall states. Nat. Commun. 6, 8474 (2015).10.1038/ncomms9474 ↗
22. Feng, Y. et al. Observation of the zero Hall plateau in a quantum anomalous Hall insulator. Phys. Rev. Lett. 115, 126801 (2015).10.1103/PhysRevLett.115.126801 ↗
23. Mogi, M. et al. Magnetic modulation doping in topological insulators toward higher-temperature quantum anomalous Hall effect. Appl. Phys. Lett. 107, 182401 (2015).10.1063/1.4935075 ↗
24. Chang, C. Z. et al. High-precision realization of robust quantum anomalous Hall state in a hard ferromagnetic topological insulator. Nat. Mater. 14, 473–477 (2015).10.1038/nmat4204 ↗
25. Hubert, A. & Schafer, R. Magnetic Domains. Springer Berlin Heidelberg, (1998).
26. Schwarz, A. et al. Visualization of the Barkhausen effect by magnetic force microscopy. Phys. Rev. Lett. 92, 077206 (2004).10.1103/PhysRevLett.92.077206 ↗
27. Bestwick, A. J. et al. Precise quantization of the anomalous Hall effect near zero magnetic field. Phys. Rev. Lett. 114, 187201 (2015).10.1103/PhysRevLett.114.187201 ↗
28. Grauer, S. et al. Coincidence of superparamagnetism and perfect quantization in the quantum anomalous Hall state. Phys. Rev. B 92, 201304 (2015).10.1103/PhysRevB.92.201304 ↗
29. Lachman, E. O. et al. Visualization of superparamagnetic dynamics in magnetic topological insulators. Sci. Adv. 1, e1500740 (2015).10.1126/sciadv.1500740 ↗
30. Liu, M. et al. Large discrete jumps observed in the transition between Chern states in a ferromagnetic topological insulator. Sci. Adv. 2, e1600167 (2016).10.1126/sciadv.1600167 ↗
31. Gregg, J. F. et al. Giant magnetoresistive effects in a single element magnetic thin film. Phys. Rev. Lett. 77, 1580–1583 (1996).10.1103/PhysRevLett.77.1580 ↗
32. Kent, A. D., Yu, J., Rudiger, U. & Parkin, S. S. P. Domain wall resistivity in epitaxial thin film microstructures. J. Phys. Condens. Matter 13, R461–R488 (2001).10.1088/0953-8984/13/25/202 ↗
33. Rugar, D. et al. Magnetic force microscopy: general principles and application to longitudinal recording media. J. Appl. Phys. 68, 1169–1183 (1990).10.1063/1.346713 ↗