Magnetic proximity-enhanced Curie temperature of Cr-doped Bi2Se3 thin films

被引：28

作者：

Baker, A. A. ^{[1
,2
]}

Figueroa, A. I. ^{[1
]}

Kummer, K. ^{[3
]}

Collins-McIntyre, L. J. ^{[2
]}

Hesjedal, T. ^{[2
,4
]}

van der Laan, G. ^{[1
]}

机构：

[1] Diamond Light Source, Magnet Spect Grp, Didcot OX11 0DE, Oxon, England

[2] Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England

[3] European Synchrotron Radiat Facil, F-38043 Grenoble, France

[4] Diamond Light Source, Didcot OX11 0DE, Oxon, England

来源：

PHYSICAL REVIEW B | 2015年 / 92卷 / 09期

基金：

英国工程与自然科学研究理事会;

关键词：

PHASE-TRANSITION; FERROMAGNETISM; DICHROISM; CRITERION;

D O I：

10.1103/PhysRevB.92.094420

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We report a study on the transition temperature T-C of Cr-doped topological insulator thin films, where an increase in the ferromagnetic onset can provide a pathway towards low-power spintronics in the future. Arrott plots, measured by surface-sensitive x-ray magnetic circular dichroism at the Cr L-2,L-3 edge as a function of field at various low temperatures, give a TC approximate to 7 K for the pristine surface. This is comparable to the bulk value of the film, which means that there is no indication that the spontaneous magnetization is different near the surface. Evaporation of a thin layer of Co onto the pristine surface of the in-situ cleaved sample increases the ordering temperature near the surface to similar to 19 K, while in the bulk it rises to similar to 10 K. X-ray absorption spectroscopy shows that Cr enters the Bi2Se3 host matrix in a divalent state, and is unchanged by the Co deposition. These results demonstrate a straightforward procedure to increase the transition temperature of doped topological insulators.

引用

页数：5

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