Stromtragende Eigenschaften von Korngrenzennetzwerken in YBa2Cu307 Bandleitern
Dr. Bernhard Holzapfel (Institut für Werkstoffforschung Dresden)

Current Carrying Properties of Grain Boundary Networks in YBa2Cu307 Coated Conductors

Abstract:
The Rolling Assisted Biaxially Textured Substrates (RABiTST) method is a very promising approach for the profitable production of long lengths of high temperature superconducting (HTS) YBa2Cu307-d (YBCO) tapes capable of carrying high currents in magnetic fields. A key to their transport properties is the grain boundary (GB) network that determines the upper limit for the critical current density. This talk will discuss first briefly the development of highly biaxially textured Ni and Ni-alloy tapes and the formation of the relevant GB network in YBCO by epitaxial film growth. Electrical transport measurements (Jc(B,T)) reflect clearly the characteristics of low angle grain boundaries and show a cross-over behavior from intergrain to intragrain limitation of the critical current density with increasing magnetic field. Fast Jc-simulations based on the exact knowledge of the underlying GB network fit very well to the measured critical current densities, indicating a good basic understanding of the critical current density in coated conductors.