Creating thin magnetic layers at the surface of Sb2Te3 topological insulators using a low-energy chromium ion beam
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Date
2020-05-11
Journal Title
Journal ISSN
Volume Title
Publisher
AIP Publishing
Abstract
The surfaces of Sb2Te3 topological insulator crystals were implanted using a 40 keV chromium ion beam. To facilitate uniform doping, the Sb2Te3 was passivated with a thin TiO2 film before the implantation step. The resulting chemical structure was studied using atomic-resolution transmission electron microscopy. A fluence of 7 × 1015 ions/cm2 at 40 keV lead to amorphization of the Sb2Te3 surface, with chromium predominantly incorporated in the amorphous layer. Heating to 200 °C caused the amorphous region to recrystallize and led to the formation of a thin chromium-rich interfacial layer. Near-edge x-ray absorption spectroscopy indicates a uniform valence state of Cr3+ throughout, with no evidence of metallic clustering. High-temperature superparamagnetic behavior was detected up to 300 K, with an increased magnetic moment below 50 K. © 2020 Author(s).
Description
Keywords
Thin Films, Ion beams, Crystal doping, Chromium, Chromium base alloys, Magnetic materials, Layers, Electrical insulators, Epitaxy, Transmission electron microscopy
Citation
Cortie, D., Zhao, W., Yue, Z., Li, Z., Bake, A., Marenych, O., Pastuovic, Z., Nancarrow, M., Zhang, Z., Qi, D.-C., Evans, P., Mitchell, D. R. G., & Wang, X. (2020). Creating thin magnetic layers at the surface of Sb2Te3 topological insulators using a low-energy chromium ion beam. Applied Physics Letters, 116(19), 192410. doi:10.1063/5.0006447