title: Spontaneous formation of a superconducting and antiferromagnetic hybrid state in SrFe2As2 under high pressure.
abstract: We report a novel superconducting (SC) and antiferromagnetic (AF) hybrid state in SrFe(2)As(2) revealed by (75)As nuclear magnetic resonance (NMR) experiments on a single crystal under highly hydrostatic pressure up to 7 GPa. The NMR spectra at 5.4 GPa indicate simultaneous development of the SC and AF orders below 30 K. The nuclear spin-lattice relaxation rate in the SC domains shows a substantial residual density of states, suggesting proximity effects due to the spontaneous formation of a nanoscale SC-AF hybrid structure. This entangled behavior is a remarkable example of a self-organized heterogeneous structure in a clean system.
authors.affiliation: Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8581, Japan. kitag@issp.u-tokyo.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Kitagawa
authors.forename: N
authors.initials: N
authors.lastname: Katayama
authors.forename: H
authors.initials: H
authors.lastname: Gotou
authors.forename: T
authors.initials: T
authors.lastname: Yagi
authors.forename: K
authors.initials: K
authors.lastname: Ohgushi
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Y
authors.initials: Y
authors.lastname: Uwatoko
authors.forename: M
authors.initials: M
authors.lastname: Takigawa