title: Coexistence of magnetism and superconductivity in the iron-based compound Cs0.8(FeSe0.98)2.
abstract: We report on muon-spin rotation and relaxation (μSR), electrical resistivity, magnetization and differential scanning calorimetry measurements performed on a high-quality single crystal of Cs(0.8)(FeSe(0.98))(2). Whereas our transport and magnetization data confirm the bulk character of the superconducting state below T(c)=29.6(2)  K, the μSR data indicate that the system is magnetic below T(N)=478.5(3)  K, where a first-order transition occurs. The first-order character of the magnetic transition is confirmed by differential scanning calorimetry data. Taken all together, these data indicate in Cs(0.8)(FeSe(0.98))(2) a microscopic coexistence between the superconducting phase and a strong magnetic phase. The observed T(N) is the highest reported to date for a magnetic superconductor.
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: Z
authors.initials: Z
authors.lastname: Shermadini
authors.forename: A
authors.initials: A
authors.lastname: Krzton-Maziopa
authors.forename: M
authors.initials: M
authors.lastname: Bendele
authors.forename: R
authors.initials: R
authors.lastname: Khasanov
authors.forename: H
authors.initials: H
authors.lastname: Luetkens
authors.forename: K
authors.initials: K
authors.lastname: Conder
authors.forename: E
authors.initials: E
authors.lastname: Pomjakushina
authors.forename: S
authors.initials: S
authors.lastname: Weyeneth
authors.forename: V
authors.initials: V
authors.lastname: Pomjakushin
authors.forename: O
authors.initials: O
authors.lastname: Bossen
authors.forename: A
authors.initials: A
authors.lastname: Amato