Study of the structural, electric and magnetic properties of Mn-doped Bi2Te3 single crystals
Breaking the time reversal symmetry of a topological insulator, for example by the presence of magnetic ions, is a prerequisite for spin-based electronic applications in the future. In this regard Mn-doped Bi _2 Te _3 is a prototypical example that merits a systematic investigation of its magnetic p...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2013-01-01
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| Series: | New Journal of Physics |
| Online Access: | https://doi.org/10.1088/1367-2630/15/10/103016 |
| _version_ | 1827874574880997376 |
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| author | M D Watson L J Collins-McIntyre L R Shelford A I Coldea D Prabhakaran S C Speller T Mousavi C R M Grovenor Z Salman S R Giblin G van der Laan T Hesjedal |
| author_facet | M D Watson L J Collins-McIntyre L R Shelford A I Coldea D Prabhakaran S C Speller T Mousavi C R M Grovenor Z Salman S R Giblin G van der Laan T Hesjedal |
| author_sort | M D Watson |
| collection | DOAJ |
| description | Breaking the time reversal symmetry of a topological insulator, for example by the presence of magnetic ions, is a prerequisite for spin-based electronic applications in the future. In this regard Mn-doped Bi _2 Te _3 is a prototypical example that merits a systematic investigation of its magnetic properties. Unfortunately, Mn doping is challenging in many host materials—resulting in structural or chemical inhomogeneities affecting the magnetic properties. Here, we present a systematic study of the structural, magnetic and magnetotransport properties of Mn-doped Bi _2 Te _3 single crystals using complimentary experimental techniques. These materials exhibit a ferromagnetic phase that is very sensitive to the structural details, with T _C varying between 9 and 13 K (bulk values) and a saturation moment that reaches 4.4(5) μ _B per Mn in the ordered phase. Muon spin rotation suggests that the magnetism is homogeneous throughout the sample. Furthermore, torque measurements in fields up to 33 T reveal an easy axis magnetic anisotropy perpendicular to the ab -plane. The electrical transport data show an anomaly around T _C that is easily suppressed by an applied magnetic field, and also anisotropic behavior due to the spin-dependent scattering in relation to the alignment of the Mn magnetic moment. Hall measurements on different crystals established that these systems are n -doped with carrier concentrations of ∼ 0.5–3.0 × 10 ^20 cm ^−3 . X-ray magnetic circular dichroism (XMCD) at the Mn L _2,3 edge at 1.8 K reveals a large spin magnetic moment of 4.3(3) μ _B /Mn, and a small orbital magnetic moment of 0.18(2) μ _B /Mn. The results also indicate a ground state of mixed d ^4 –d ^5 –d ^6 character of a localized electronic nature, similar to the diluted ferromagnetic semiconductor Ga _1− _x Mn _x As. XMCD measurements in a field of 6 T give a transition point at T ≈ 16 K, which is ascribed to short range magnetic order induced by the magnetic field. In the ferromagnetic state the easy direction of magnetization is along the c -axis, in agreement with bulk magnetization measurements. This could lead to gap opening at the Dirac point, providing a means to control the surface electric transport, which is of great importance for applications. |
| first_indexed | 2024-03-12T16:53:49Z |
| format | Article |
| id | doaj.art-a048ad3a2374425faba5e8712d0f5abf |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:53:49Z |
| publishDate | 2013-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-a048ad3a2374425faba5e8712d0f5abf2023-08-08T11:03:34ZengIOP PublishingNew Journal of Physics1367-26302013-01-01151010301610.1088/1367-2630/15/10/103016Study of the structural, electric and magnetic properties of Mn-doped Bi2Te3 single crystalsM D Watson0L J Collins-McIntyre1L R Shelford2A I Coldea3D Prabhakaran4S C Speller5T Mousavi6C R M Grovenor7Z Salman8S R Giblin9G van der Laan10T Hesjedal11Clarendon Laboratory, Department of Physics, University of Oxford , Oxford OX1 3PU, UKClarendon Laboratory, Department of Physics, University of Oxford , Oxford OX1 3PU, UKMagnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE, UKClarendon Laboratory, Department of Physics, University of Oxford , Oxford OX1 3PU, UKClarendon Laboratory, Department of Physics, University of Oxford , Oxford OX1 3PU, UKDepartment of Materials, University of Oxford , Oxford OX1 3PH, UKDepartment of Materials, University of Oxford , Oxford OX1 3PH, UKDepartment of Materials, University of Oxford , Oxford OX1 3PH, UKLaboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut , CH-5232 Villigen, SwitzerlandSchool of Physics and Astronomy, Cardiff University , Cardiff CF24 3AA, UKMagnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE, UKClarendon Laboratory, Department of Physics, University of Oxford , Oxford OX1 3PU, UKBreaking the time reversal symmetry of a topological insulator, for example by the presence of magnetic ions, is a prerequisite for spin-based electronic applications in the future. In this regard Mn-doped Bi _2 Te _3 is a prototypical example that merits a systematic investigation of its magnetic properties. Unfortunately, Mn doping is challenging in many host materials—resulting in structural or chemical inhomogeneities affecting the magnetic properties. Here, we present a systematic study of the structural, magnetic and magnetotransport properties of Mn-doped Bi _2 Te _3 single crystals using complimentary experimental techniques. These materials exhibit a ferromagnetic phase that is very sensitive to the structural details, with T _C varying between 9 and 13 K (bulk values) and a saturation moment that reaches 4.4(5) μ _B per Mn in the ordered phase. Muon spin rotation suggests that the magnetism is homogeneous throughout the sample. Furthermore, torque measurements in fields up to 33 T reveal an easy axis magnetic anisotropy perpendicular to the ab -plane. The electrical transport data show an anomaly around T _C that is easily suppressed by an applied magnetic field, and also anisotropic behavior due to the spin-dependent scattering in relation to the alignment of the Mn magnetic moment. Hall measurements on different crystals established that these systems are n -doped with carrier concentrations of ∼ 0.5–3.0 × 10 ^20 cm ^−3 . X-ray magnetic circular dichroism (XMCD) at the Mn L _2,3 edge at 1.8 K reveals a large spin magnetic moment of 4.3(3) μ _B /Mn, and a small orbital magnetic moment of 0.18(2) μ _B /Mn. The results also indicate a ground state of mixed d ^4 –d ^5 –d ^6 character of a localized electronic nature, similar to the diluted ferromagnetic semiconductor Ga _1− _x Mn _x As. XMCD measurements in a field of 6 T give a transition point at T ≈ 16 K, which is ascribed to short range magnetic order induced by the magnetic field. In the ferromagnetic state the easy direction of magnetization is along the c -axis, in agreement with bulk magnetization measurements. This could lead to gap opening at the Dirac point, providing a means to control the surface electric transport, which is of great importance for applications.https://doi.org/10.1088/1367-2630/15/10/103016 |
| spellingShingle | M D Watson L J Collins-McIntyre L R Shelford A I Coldea D Prabhakaran S C Speller T Mousavi C R M Grovenor Z Salman S R Giblin G van der Laan T Hesjedal Study of the structural, electric and magnetic properties of Mn-doped Bi2Te3 single crystals New Journal of Physics |
| title | Study of the structural, electric and magnetic properties of Mn-doped Bi2Te3 single crystals |
| title_full | Study of the structural, electric and magnetic properties of Mn-doped Bi2Te3 single crystals |
| title_fullStr | Study of the structural, electric and magnetic properties of Mn-doped Bi2Te3 single crystals |
| title_full_unstemmed | Study of the structural, electric and magnetic properties of Mn-doped Bi2Te3 single crystals |
| title_short | Study of the structural, electric and magnetic properties of Mn-doped Bi2Te3 single crystals |
| title_sort | study of the structural electric and magnetic properties of mn doped bi2te3 single crystals |
| url | https://doi.org/10.1088/1367-2630/15/10/103016 |
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