Cr2Te3 Thin Films for Integration in Magnetic Topological Insulator Heterostructures

D M Burn; L B Duffy; R Fujita; S L Zhang; A I Figueroa; J Herrero-Martin; G van der Laan; T Hesjedal

doi:10.1038/s41598-019-47265-7

Cr₂Te₃ Thin Films for Integration in Magnetic Topological Insulator Heterostructures

Sci Rep. 2019 Jul 25;9(1):10793. doi: 10.1038/s41598-019-47265-7.

Authors

D M Burn¹, L B Duffy^{2

3}, R Fujita^{1

2}, S L Zhang², A I Figueroa^{1

4}, J Herrero-Martin⁵, G van der Laan¹, T Hesjedal⁶

Affiliations

¹ Magnetic Spectroscopy Group, Diamond Light Source, Didcot, OX11 0DE, United Kingdom.
² Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom.
³ ISIS, Rutherford Appleton Laboratory, Science and Technology Facilities Council, Oxon, OX11 0QX, United Kingdom.
⁴ Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC, Campus UAB, Barcelona, 08193, Spain.
⁵ CELLS-Divisió Experiments, ALBA Synchrotron Light Source, E-08290 Cerdanyola del Vallès, Barcelona, Catalonia, Spain.
⁶ Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom. Thorsten.Hesjedal@physics.ox.ac.uk.

Abstract

Chromium telluride compounds are promising ferromagnets for proximity coupling to magnetic topological insulators (MTIs) of the Cr-doped (Bi,Sb)₂(Se,Te)₃ class of materials as they share the same elements, thus simplifying thin film growth, as well as due to their compatible crystal structure. Recently, it has been demonstrated that high quality (001)-oriented Cr₂Te₃ thin films with perpendicular magnetic anisotropy can be grown on c-plane sapphire substrate. Here, we present a magnetic and soft x-ray absorption spectroscopy study of the chemical and magnetic properties of Cr₂Te₃ thin films. X-ray magnetic circular dichroism (XMCD) measured at the Cr L_2,3 edges gives information about the local electronic and magnetic structure of the Cr ions. We further demonstrate the overgrowth of Cr₂Te₃ (001) thin films by high-quality Cr-doped Sb₂Te₃ films. The magnetic properties of the layers have been characterized and our results provide a starting point for refining the physical models of the complex magnetic ordering in Cr₂Te₃ thin films, and their integration into advanced MTI heterostructures for quantum device applications.