Growth and characterizations of Ba2Ti2Fe2As4O single crystals

Yun-Lei Sun; Abduweli Ablimit; Jin-Ke Bao; Hao Jiang; Jie Zhou; Guang-Han Cao

doi:10.1088/1468-6996/14/5/055008

Growth and characterizations of Ba₂Ti₂Fe₂As₄O single crystals

Sci Technol Adv Mater. 2013 Oct 22;14(5):055008. doi: 10.1088/1468-6996/14/5/055008. eCollection 2013 Oct.

Authors

Yun-Lei Sun¹, Abduweli Ablimit¹, Jin-Ke Bao¹, Hao Jiang¹, Jie Zhou¹, Guang-Han Cao²

Affiliations

¹ Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China.
² Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China; State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027, People's Republic of China.

Abstract

Single crystals of a new iron-based superconductor Ba₂Ti₂Fe₂As₄O have been grown successfully via a Ba₂As₃-flux method in a sealed evacuated quartz tube. Bulk superconductivity with T_c ∼ 21.5 K was demonstrated in resistivity and magnetic susceptibility measurements after the as-grown crystals were annealed at 500 °C in vacuum for a week. X-ray diffraction patterns confirm that the annealed and the as-grown crystals possess the identical crystallographic structure of Ba₂Ti₂Fe₂As₄O. Energy-dispersive x-ray spectra indicate that partial Ti/Fe substitution exists in the [Fe₂As₂] layers and the annealing process redistributes the Ti within the Fe-plane. The ordered Fe-plane stabilized by annealing exhibits superconductivity with magnetic vortex pinned by Ti.

Keywords: Ba2Ti2Fe2As4O; iron-based superconductor; single crystal growth.