Preparation of Fe-oxypnictides superconductors: Solid-state sintering, high pressure synthesis and flux method

We have fabricated the F-doped LaFeAsO superconductors via three fabrication processes; (1) solid-state sintering, (2) high pressure (HP) synthesis and (3) crystallization from flux solution. Samples prepared by these processes have unique features depending on the process such as a large volume and uniformity of the sintered pellet, variety of the compositions in the high pressured pellet and potential of growing large single crystal using fluxes. In particular, the HP synthetic process has a unique advantage that the compositional variations in the compounds were realized by a large temperature gradient within a short reaction time.