  Mn-doped SrTiO_3.0, when synthesized free of impurities, is a paramagnetic
insulator with interesting dielectric properties. Since delocalized charge
carriers are known to promote ferromagnetism in a large number of systems via
diverse mechanisms, we have looked for the possibility of any intrinsic,
spontaneous magnetization by simultaneous doping of Mn ions and electrons into
SrTiO_3 via oxygen vacancies, thereby forming SrTi_(1-x)Mn_xO_(3-d), to the
extent of making the doped system metallic. We find an absence of any
enhancement of the magnetization in the metallic sample when compared with a
similarly prepared Mn doped, however, insulating sample. Our results, thus, are
not in agreement with a recent observation of a weak ferromagnetism in metallic
Mn doped SrTiO_3 system.
