High Critical Current Densities and Angular Dependence in MgB2-stainless steel (SS) Tapes

G. SERRANO; A. SERQUIS; L. CIVALE; B. MAIOROV; M. T. MALACHEVSKY; M. JAIME; F. BALAKIREV; G. BRIDOUX; E. OSQUIGUIL; C. AYALA

Bruselas – 16-20 September 2007

Conferencia; EUCAS 2007; 2007

European Conference on Applied Superconductivity

We present a study on the angular dependence of SiC-doped MgB2 tapes fabricated with stainless steel (SS) sheaths by powder-in tube (PIT) using drawing and cold rolling with different heat treatments between 600 and 900ºC. The microstructure is studied by x-ray diffraction, transmission and scanning electron microscopy. The critical temperature (Tc) and the angular dependence of the critical current density (Jc), irreversibility (Hirr) and upper critical (Hc2) fields are determined by transport measurements.The microstructure and a-b texturing of the tapes are analyzed to understand the effects of the fabrication parameters over final superconducting properties. We show that after rolling the obtained samples are as dense as those wires processed using hot isostatic pressing (HIPing), and they also have similar superconducting properties, such as a Jc of ~104A/cm2 at H=7T and T=4.2K, while that Hirr ~ 13T and Hc2 ~ 19T at T=4.2K. The Hc2 anisotropy, as well as the angular dependence of Jc different fields and temperatures, can be correlated with the degree of rolling, which in turn determines the anisotropy cross sectional aspect ratio and the degree of a-b texturing.