Local destruction of superconductivity by non-magnetic impurities in mesoscopic iron-based superconductors.

The determination of the pairing symmetry is one of the most crucial issues for the iron-based superconductors, for which various scenarios are discussed controversially. Non-magnetic impurity substitution is one of the most promising approaches to address the issue, because the pair-breaking mechanism from the non-magnetic impurities should be different for various models. Previous substitution experiments demonstrated that the non-magnetic zinc can suppress the superconductivity of various iron-based superconductors.

High-temperature ferrimagnetism driven by lattice distortion in double perovskite Ca2FeOsO6.

5d and 3d hybrid solid-state oxide Ca2FeOsO6 crystallizes into an ordered double-perovskite structure with a space group of P2₁/n with high-pressures and temperatures. Ca2FeOsO6 presents a long-range ferrimagnetic transition at a temperature of ~320 K (T(c)) and is not a band insulator, but is electrically insulating like the recently discovered Sr2CrOsO6 (T(c) ~725 K). The electronic stat of Ca2FeOsO6 is adjacent to a half-metallic state as well as that of Sr2CrOsO6.