Development of Textured Buffer Layer on Metal Tapes for Oxide Superconductors

Abstract : Report documents the development effort dedicated to the scale up of inclined substrate deposition (ISD) of textured magnesium oxide (MgO) on continuous tapes of nickel based alloys under an AFOSR Phase II STTR program, in partnership with Argonne National Laboratory (ANL). Long length highly textured MgO template has been successfully deposited on HC substrate in the reel-to-reel system. High deposition rate up to 10 nm/sec of the ISD MgO ebeam deposition and broad exposure window of 7 cm have been achieved with the average in-plane texture of FWHM=10. With this set up the output of the well textured MgO template can be easily reached to 1 m/hr. Texture formation of the MgO layer has been investigated by XRD analysis. A new relationship termed "two-third relationship" between inclined angle and the tilted angle of (001) plane is found for the present experimental set up. YBCO-coated conductors fabricated on lightly polished Hastelloy C(HC) substrate with the ISD-MgO capped with Strontium Ruthenate (SRO) buffer layer exhibited a sharp transition with Tc = 90 K. Transport Jc = 0.68x 10(exp 6) A/sq cm and Ic > 44 A/cm were measured at 77 K in self-field. Using highly polished HC surface, Jc increased to over 1.6 x 10(exp 6) A/sq cm and I(sub c) increased to 110 A/cm.