Magnetic ordering in Ho-doped Bi2Te3 topological insulator

A. I. Figueroa; S. E. Harrison; L. J. Collins-Mcintyre; G. van der Laan; T. Hesjedal

doi:10.1002/pssr.201600061

Magnetic ordering in Ho-doped Bi₂Te₃ topological insulator

A. I. Figueroa, S. E. Harrison, L. J. Collins-Mcintyre, G. van der Laan, T. Hesjedal^*

^*Corresponding author for this work

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

Abstract

We investigate the magnetic properties of Ho-doped Bi₂Te₃ thin films grown by molecular beam epitaxy. Analysis of the polarized X-ray absorption spectra at the Ho M₅ absorption edge gives an effective 4f magnetic moment which is ∼45% of the Hund's rule ground state value. X-ray magnetic circular dichroism (XMCD) shows no significant anisotropy, which suggests that the reduced spin moment is not due to the crystal field effects, but rather the presence of non-magnetic or antiferromagnetic Ho sites. Extrapolating the temperature dependence of the XMCD measured in total electron yield and fluorescence yield mode in a field of 7 T gives a Curie-Weiss temperature of θ _CW ≈ -30 K, which suggests antiferromagnetic ordering, in contrast to the paramagnetic behavior observed with SQUID magnetometry. From the anomaly of the XMCD signal at low temperatures, a Néel temperature T_N between 10 K and 25 K is estimated.

Original language	English
Pages (from-to)	467-470
Journal	Physica Status Solidi - Rapid Research Letters
Volume	10
Issue number	6
Early online date	14 Apr 2016
DOIs	https://doi.org/10.1002/pssr.201600061
Publication status	Published - Jun 2016

Keywords

Antiferromagnetism
Doping
Magnetic ordering
Molecular beam epitaxy
Topological insulators
X-ray magnetic circular dichroism

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10.1002/pssr.201600061

Figueroa_2016_Magnetic_PSS_AAM
© 2016, Wiley-VCH Verlag GmbH & Co . This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at onlinelibrary.wiley.com / https://dx.doi.org/10.1002/pssr.201600061
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Cite this

@article{5c548c107d414444b6c57b2a8808c901,

title = "Magnetic ordering in Ho-doped Bi2Te3 topological insulator",

abstract = "We investigate the magnetic properties of Ho-doped Bi2Te3 thin films grown by molecular beam epitaxy. Analysis of the polarized X-ray absorption spectra at the Ho M5 absorption edge gives an effective 4f magnetic moment which is ∼45% of the Hund's rule ground state value. X-ray magnetic circular dichroism (XMCD) shows no significant anisotropy, which suggests that the reduced spin moment is not due to the crystal field effects, but rather the presence of non-magnetic or antiferromagnetic Ho sites. Extrapolating the temperature dependence of the XMCD measured in total electron yield and fluorescence yield mode in a field of 7 T gives a Curie-Weiss temperature of θ CW ≈ -30 K, which suggests antiferromagnetic ordering, in contrast to the paramagnetic behavior observed with SQUID magnetometry. From the anomaly of the XMCD signal at low temperatures, a N{\'e}el temperature TN between 10 K and 25 K is estimated.",

keywords = "Antiferromagnetism, Doping, Magnetic ordering, Molecular beam epitaxy, Topological insulators, X-ray magnetic circular dichroism",

author = "Figueroa, {A. I.} and Harrison, {S. E.} and Collins-Mcintyre, {L. J.} and {van der Laan}, G. and T. Hesjedal",

note = "This publication arises from research funded by the John Fell Oxford University Press (OUP) Research Fund and the Research Complex at Harwell is acknowledged for their hospitality. SEH acknowledges partial financial support from a DARPA MESO Project (No. N66001-11-1-4105) and the VPGE (Stanford University) and LCM partial financial support from EPSRC (UK) through a Doctoral Training Award.",

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AU - Figueroa, A. I.

AU - Harrison, S. E.

AU - Collins-Mcintyre, L. J.

AU - van der Laan, G.

AU - Hesjedal, T.

N1 - This publication arises from research funded by the John Fell Oxford University Press (OUP) Research Fund and the Research Complex at Harwell is acknowledged for their hospitality. SEH acknowledges partial financial support from a DARPA MESO Project (No. N66001-11-1-4105) and the VPGE (Stanford University) and LCM partial financial support from EPSRC (UK) through a Doctoral Training Award.

PY - 2016/6

Y1 - 2016/6

N2 - We investigate the magnetic properties of Ho-doped Bi2Te3 thin films grown by molecular beam epitaxy. Analysis of the polarized X-ray absorption spectra at the Ho M5 absorption edge gives an effective 4f magnetic moment which is ∼45% of the Hund's rule ground state value. X-ray magnetic circular dichroism (XMCD) shows no significant anisotropy, which suggests that the reduced spin moment is not due to the crystal field effects, but rather the presence of non-magnetic or antiferromagnetic Ho sites. Extrapolating the temperature dependence of the XMCD measured in total electron yield and fluorescence yield mode in a field of 7 T gives a Curie-Weiss temperature of θ CW ≈ -30 K, which suggests antiferromagnetic ordering, in contrast to the paramagnetic behavior observed with SQUID magnetometry. From the anomaly of the XMCD signal at low temperatures, a Néel temperature TN between 10 K and 25 K is estimated.

AB - We investigate the magnetic properties of Ho-doped Bi2Te3 thin films grown by molecular beam epitaxy. Analysis of the polarized X-ray absorption spectra at the Ho M5 absorption edge gives an effective 4f magnetic moment which is ∼45% of the Hund's rule ground state value. X-ray magnetic circular dichroism (XMCD) shows no significant anisotropy, which suggests that the reduced spin moment is not due to the crystal field effects, but rather the presence of non-magnetic or antiferromagnetic Ho sites. Extrapolating the temperature dependence of the XMCD measured in total electron yield and fluorescence yield mode in a field of 7 T gives a Curie-Weiss temperature of θ CW ≈ -30 K, which suggests antiferromagnetic ordering, in contrast to the paramagnetic behavior observed with SQUID magnetometry. From the anomaly of the XMCD signal at low temperatures, a Néel temperature TN between 10 K and 25 K is estimated.

KW - Antiferromagnetism

KW - Doping

KW - Magnetic ordering

KW - Molecular beam epitaxy

KW - Topological insulators

KW - X-ray magnetic circular dichroism

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DO - 10.1002/pssr.201600061

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JO - Physica Status Solidi - Rapid Research Letters

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