Comparative study of Fe(Se,Te) thin films on flexible coated conductor templates and single-crystal substrates

Abstract

In this paper, we compare epitaxial Fe(Se,Te) thin films grown by pulsed laser deposition on CaF2, SrTiO3, MgO single crystals as well as on different metallic templates having a CeO2 based top surface. In particular, we performed a detailed structural and superconducting analysis. X-ray diffraction studies showed highly textured films on all templates. The superconducting transition temperatures are between 21 K and 14 K for Fe(Se,Te) films on CaF2 and on MgO single-crystal substrates, respectively, whereas films on the metal templates show T c values up to 18 K. The critical current density (J c) was determined from magnetization loops in fields up to 7 T. Calculations in the framework of the extended critical state model showed J c values over 2 MA cm−2 and 0.9 MA cm−2 at 5 K in self-field on single-crystal substrates and metal templates substrates, respectively. Detailed transmission electron microscopy studies reveal smooth layers on all templates. Whereas small defects were found in films on single crystals, pronounced grain boundaries with higher misorientation angle were visible in the layers on metallic templates.

Performance improvement of iron chalcogenide films grown at high laser repetition rates by pulsed laser deposition

“…The modified FST film has a self-field J c of MA/cm 2 at K, is comparable to the current-carrying capacity of the FST films grown at low laser repetition rates (on the order of MA/cm 2 ). 17,[55][56][57] Although the J c of the modified FST film declines with increasing magnetic field because of flux creep, it can still reach 0.3 MA/cm 2 at 9 T and 4.2 K.…”

Critical Role Played by Interface Engineering in Weakening Thickness Dependence of Superconducting and Structural Properties of FeSe0.5Te0.5-Coated Conductors

“…Within the IBS family, 11 family, such as FeSe or FeSe 1– x Te x (FST), is particularly attractive due to its simple crystal structure, ease of synthesis, and lack of toxic elements, receiving enormous interest in the scientific community. Therefore, tremendous efforts have been devoted to realizing the potential applications of this material class in a high field, and high-performance 11 family superconducting wires and tapes have been successfully fabricated by both the powder-in-tube (PIT) method − and the coated conductor (CC) strategy. − In spite of its simpler structure than other IBSs, the 11 family has a complicated phase diagram, which requires precise chemical composition control and heat treatment to produce superconducting α-FST phases. Thus, the PIT-processed wires and tapes usually exhibit poor superconducting performance owing to the high reactivity of the FST phase with metallic sheath materials and difficulties in phase and composition control.…”

Magnetic granularity in PLD-grown Fe(Se,Te) films on simple RABiTS templates

“…The upper critical field in the iron-based superconductors (IBS) are similarly high [7,8], but the texture requirement seems relaxed, since this class of materials allows for a higher misorientation angle between neighboring grains before the current across the respective grain boundary (GB) is heavily suppressed [7,9,10]. This could enable cheap production techniques, such as powder in tube [8,[11][12][13], or at least simplify the architecture and production of coated conductors [7,[14][15][16][17][18][19][20][21]. A comparably cheap production method for coated conductors is based on the use of rolling assisted biaxially textured substrates (RABiTS).…”