MgB 2 double-sided thick films fabricated on various metals by electrophoresis method

Abstract

The paper reports a remarkably simple method for fast fabrication of double-sided MgB 2 thick films by electrophoresing precursor boron powders on various metallic substrates followed by an ex situ annealing in magnesium vapor. Both sides of the films are homogeneous in thickness and composition, and no significant difference in T c and J c is found between the MgB 2 thick films on both sides of metals. Scanning electron microscopy on both sides of the double-sided films show dense and homogeneous structure consisting of MgB 2 grains below 1 μm. The X-ray diffraction and resistance measurement of the MgB 2 thick films on different metals show that the films are random oriented and have the onset superconducting temperature T c in the range of about 32–38 K. Estimates using hysteresis loops and Bean model give the critical current densities of the thick films are above 10 5 A/cm 2 in zero field and 5 K. The irreversibility fields of the thick films are comparable to those obtained from the dense wire.