IRON-SEA · Establishing the basic science and technology for Iron-based superconducting electronics applications

Recent investigations on iron-based superconductors have revealed a lot of similarities to MgB2 and the cuprates, for instance, a multiband nature, high upper critical fields and a short coherence length. Now immediate interest of a new class of materials would be exploring potential electronics applications such as Josephson devices and SQUIDs. In this project, we will address the feasibility of electronics applications by establishing the fundamentals of the iron-based superconductors.Examining the Josephson effect and SQUIDs, the so-called phase-sensitive experiment, also paves the way to understanding fundamental properties such as order parameters symmetry and energy gap, which is one of the main objective in this project. Investigations by point contact spectroscopy, infrared spectroscopy and transport properties are also conducted within the same frame of this work. Such fundamental studies may find unique physical properties, which lead to exploring new kinds of devices and applications. Since the iron-based superconductors are multi-band natures, comparative studies to MgB2 are also carried out. The obtained results are interpreted based on modelling and theory, which will also guide for designing better junctions.We will investigate various kinds of the iron-based superconducting films, involving K-doped SrFe2As2 (Sr-122), Co-doped BaFe2As2 (Ba-122), Te containing FeSe (11), F-doped NdFeAsO (Nd-1111) and LaFeAsO (La-1111). To date, the in-situ growth of both K-doped Sr-122 and F-doped Nd-1111 have been prepared by molecular beam epitaxy, MBE, only in this consortium. High quality, Co-doped Ba-122 and Te containing 11 epitaxial films by pulsed laser deposition are usable for this project, since the deposition condition for both films have been almost optimized by the individual groups within this consortium.