title: Emergence of superconductivity in "32522" structure of (Ca3Al2O(5-y))(Fe2Pn2) (Pn = As and P).
abstract: Using a high-pressure technique, we have successfully synthesized (Ca(3)Al(2)O(5-y))(Fe(2)Pn(2)) (Pn = As and P), the first iron-based superconductors with the perovskite-based "32522" structure to be reported. The transition temperature (T(c)) is 30.2 K for Pn = As and 16.6 K for Pn = P. The emergence of superconductivity is ascribed to the small tetragonal a-axis lattice constant of the materials. From these results, an empirical relationship is established between the a-axis lattice constant and T(c) in iron-based superconductors, which offers a practical guideline for exploring new superconductors with higher T(c).
authors.affiliation: National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan. paras-shirage@aist.go.jp
authors.forename: Parasharam M
authors.initials: PM
authors.lastname: Shirage
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Kihou
authors.forename: Chul-Ho
authors.initials: CH
authors.lastname: Lee
authors.forename: Hijiri
authors.initials: H
authors.lastname: Kito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Eisaki
authors.forename: Akira
authors.initials: A
authors.lastname: Iyo