Structure of the Li1+xTi2−xO4 superconducting system: A neutron diffraction study

The location of the Li+ ions in the superconducting Li1+xTi2-xO4 solid solution (0 less-than-or-equal-to x less-than-or-equal-to 0.33) has been determined by refinement of time-of-flight powder neutron diffraction data. The spinel structure is maintained throughout, with the substituting Li + directly replacing the Ti ions on the spinel B-sites (16d). AC susceptibility measurements of the superconducting transitions revealed a slight reduction in T(c) and a rapid reduction in the apparent volume fraction of superconductor at the metal-insulator boundary (x almost-equal-to 0.15), whilst for x < 0.1 little difference in the superconducting properties was observed.