Publications associated with Thin Film Quantum Materials

Magnetic ordering in Ho-doped Bi<inf>2</inf>Te<inf>3</inf> topological insulator

Physica Status Solidi - Rapid Research Letters 10 (2016) 467-470

AI Figueroa, SE Harrison, LJ Collins-McIntyre, G van der Laan, T Hesjedal

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimWe 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 ϑCW ≈ –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. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim).

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