title: Growth of c-axis-oriented superconducting KFe₂As₂ thin films.
abstract: KFe2As2, an iron-based superconductor, is expected to exhibit large spin Hall conductivity, and fabrication of high-quality thin films is requisite for evaluation of this effect and application to spintronics devices. Thin-film growth of KFe2As2 is difficult because of two intrinsic properties; its extremely hygroscopic nature and the high vapor pressure of potassium. We solved these issues by combining room-temperature pulsed laser deposition using K-rich KFe2As2 targets with thermal crystallization in KFe2As2 powder after encapsulation in an evacuated silica-glass tube with all of the processes conducted in a vacuum chamber and a dry Ar atmosphere in a glovebox. The optimized KFe2As2 films on (La,Sr)(Al,Ta)O3 single-crystal substrates were obtained by crystallization at 700 °C, and they were strongly c-axis oriented. The electrical measurements were performed with thin films protected by grease passivation to block reaction with the atmosphere. The KFe2As2 films exhibited a superconductivity transition at 3.7 K.
authors.affiliation: Materials and Structures Laboratory, Tokyo Institute of Technology , Mailbox R3-1, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Hiramatsu
authors.forename: Shogo
authors.initials: S
authors.lastname: Matsuda
authors.forename: Hikaru
authors.initials: H
authors.lastname: Sato
authors.forename: Toshio
authors.initials: T
authors.lastname: Kamiya
authors.forename: Hideo
authors.initials: H
authors.lastname: Hosono