Parent phase and superconductors in the fluorine derivative family

The family of fluoride-arsenide AeFeAsF compounds (Ae = alkaline earth elements or other divalent elements) with the ZrCuSiAs structure was successfully fabricated and investigated. The resistivity and magnetic anomalies associated with the structural phase transition or Antiferromagnetic (AF) transition were found to occur at about 173 K for SrFeAsF, 118 K for CaFeAsF and 153 K for EuFeAsF, respectively. The Hall coefficients RH of two parent phases, SrFeAsF and CaFeAsF, were measured and found to be positive at low temperatures. By doping rare earth elements into the system, superconductivity was induced. Superconductivity at 29.5 K in Sr0.6La0.4FeAsF and beyond 50 K in Ca0.4Re0.6FeAsF (RE = rare earth elements) was successfully obtained. More superconductors are expectable in this family by doping charges into the system in multiple ways.