Experimental Verification of the Van Vleck Nature of Long-Range Ferromagnetic Order in the Vanadium-Doped Three-Dimensional Topological Insulator Sb[subscript 2]Te[subscript 3]

• Main Authors: Li, Mingda (Contributor), Wu, Lijun (Author), Tao, Jing (Author), Zhao, Weiwei (Author), Chan, Moses H. W (Author), Li, Ju (Contributor), Zhu, Yimei (Author), Chang, Cui-zu (Contributor), Moodera, Jagadeesh (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Nuclear Science and Engineering (Contributor), Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Plasma Science and Fusion Center (Contributor), Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology) (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2015-04-17T12:39:57Z.
• Subjects: Article
• Online Access: Get fulltext

 We demonstrate by high resolution low temperature electron energy loss spectroscopy (EELS) measurements that the long range ferromagnetic (FM) order in the vanadium- (V-)doped topological insulator Sb[subscript 2]Te[subscript 3] has the nature of van Vleck-type ferromagnetism. The positions and the relative amplitudes of two core-level peaks (L[subscript 3] and L[subscript 2]) of the V EELS spectrum show unambiguous change when the sample is cooled from room temperature to T = 10  K. Magnetotransport and comparison of the measured and simulated EELS spectra confirm that these changes originate from the onset of FM order. Crystal field analysis indicates that in V-doped Sb[subscript 2]Te[subscript 3], partially filled core states contribute to the FM order. Since van Vleck magnetism is a result of summing over all states, this magnetization of core level verifies the van Vleck-type ferromagnetism in a direct manner.