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arXiv · 1611.03603

Antiferromagnetic order in epitaxial FeSe films on SrTiO3

Y. Zhou·L. Miao·P. Wang·F. F. Zhu·W. X. Jiang·S. W. Jiang·Y. Zhang·H. F. Ding·H. Zheng·J. F. Jia·D. Qian·D. Wu
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Abstract

Single monolayer FeSe film grown on Nb-doped SrTiO$_3$(001) substrate shows the highest superconducting transition temperature (T$_C$ $\sim$ 100 K) among the iron-based superconductors (iron-pnictide), while T$_C$ of bulk FeSe is only $\sim$ 8 K. Antiferromagnetic spin fluctuations were believed to be crucial in iron-pnictides, which has inspired several proposals to understand the FeSe/SrTiO$_3$ system. Although bulk FeSe does not show the antiferromagnetic order, calculations suggest that the parent FeSe/SrTiO$_3$ films are AFM. Experimentally, due to lacking of direct probe, the magnetic state of FeSe/SrTiO$_3$ films remains mysterious. Here, we report the direct evidences of the antiferromagnetic order in the parent FeSe/SrTiO$_3$ films by the magnetic exchange bias effect measurements. The phase transition temperature is $\geq$ 140 K for single monolayer film. The AFM order disappears after electron doping.

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Y. Zhou, L. Miao, P. Wang, F. F. Zhu, W. X. Jiang, S. W. Jiang, Y. Zhang, H. F. Ding, H. Zheng, J. F. Jia, D. Qian, D. Wu. 2017-11-09. Antiferromagnetic order in epitaxial FeSe films on SrTiO3. https://doi.org/10.1103/physrevlett.120.097001

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