  In this paper we report the results of the synthesis and structural,
transport and magnetic characterization of pure La0.5Sr1.5MnO4 (LSMO) and 5%
doped samples, i.e. La0.5Sr1.5Mn0.95B0.05O4, where B = Ru, Co and Ni. It is
shown that even a light doping is successful in suppressing the charge and
orbital ordering found for the pure LSMO. In general, doping favours the
carrier motion and, from a magnetic point of view, the set-up a spin-glass
state. Moreover, structural parameters show an anisotropy in the lattice
constant variation, with the tetragonal distortion increasing as the cell
volume reduces, which may suggest a variation in the relative nature of the
orbital character of the eg electrons along with the overall cation size.
