Number 50 (Story #1), October 3, 1991 by Phillip F. Schewe and Ben Stein CRITICAL CURRENT DENSITIES IN SUPERCONDUCTORS can be influenced with electric fields. Alex Müller, Georg Bednorz, and their colleagues at the IBM research center in Zurich incorporated a thin (70 angstroms) YBaCuO superconductor into a heterostructure transistor. This scheme provided electric fields as high as 2 x 105 V/cm; the presence of the fields modified critical current densities in the superconductor by as much as 50%. The researchers are also hoping to understand what effect the electric fields have on the movement of magnetic vortex lines inside superconductors. (Upcoming article in Physical Review Letters.)