Single monolayer FeSe film grown on Nb-doped SrTiO3(001) substrate shows the highest superconducting transition temperature (TC∼ 100 K) among the iron-based superconductors (iron-pnictide), while TC of bulk FeSe is only ∼ 8 K. Antiferromagnetic spin fluctuations were believed to be crucial in iron-pnictides, which has inspired several proposals to understand the FeSe/SrTiO3 system. Although bulk FeSe does not show the antiferromagnetic order, calculations suggest that the parent FeSe/SrTiO3 films are AFM. Experimentally, due to lacking of direct probe, the magnetic state of FeSe/SrTiO3 films remains mysterious. Here, we report the direct evidences of the antiferromagnetic order in the parent FeSe/SrTiO3 films by the magnetic exchange bias effect measurements. The phase transition temperature is ≥ 140 K for single monolayer film. The AFM order disappears after electron doping.
@article{arxiv.1611.03603,
title = {Antiferromagnetic order in epitaxial FeSe films on SrTiO3},
author = {Y. Zhou and L. Miao and P. Wang and F. F. Zhu and W. X. Jiang and S. W. Jiang and Y. Zhang and H. F. Ding and H. Zheng and J. F. Jia and D. Qian and D. Wu},
journal= {arXiv preprint arXiv:1611.03603},
year = {2018}
}