Solution deposition planarization of long-length flexible substrates

Abstract

Solution deposition planarization (SDP) is studied for preparing smooth flexible substrates in multimeter lengths. We demonstrate 0.5 nm rms surface roughness starting from unpolished metal tapes and a correlation of substrate roughness with the texture of subsequent ion-beam aligned films. Surface roughness reduction in SDP is modeled via film shrinkage during solution deposition and a residual roughness based on film thickness. Use of solution deposited a-Y2O3 to planarize substrates prior to ion-beam textured MgO growth shows an in-plane texture of MgO down to 4°. Utilizing these templates, we demonstrated superconducting YBa2Cu3Oy coated conductors with critical current densities of 2.8–4.0 MA/cm2 at 75 K.