Number 103 (Story #2), November 17, 1992 by Phillip F. Schewe and Ben Stein VORTICES IN HEAVY-FERMION SUPERCONDUCTORS have been imaged for the first time. In certain materials---in this case, a uranium-platinum compound---superconductivity can occur at temperatures below 1 K through the interactions of inner-shell electrons which, because they are tightly bound, move as if they were heavier than normal electrons. Like the high-temperature superconductors, the heavy-fermion superconductors can respond to the presence of an external magnetic field by producing vortices, little loops of current flowing around the magnetic flux lines. Studies of vortices in other superconductors indicate that they can form a sort of "lattice" configuration. Now a group of scientists at AT&T Bell Labs (David J. Bishop, 908-582-3927) and the RISO National Lab in Denmark have used neutron diffraction to show that vortices in a heavy-fermion material, UPt3, assume an oblique hexagonal structure. (R.N. Kleiman et al., Phys. Rev. Lett., 23 Nov. 1992.)