  We report the fabrication of MgB2 with bulk superconducting properties by
conventional solid state methods at temperatures as low as 550 C. Mg
deficiencies of the type Mg1-xB2 were tested. Tc was found to decrease by about
1K at large x, though the amount of non-stoichiometry, if any, is likely to be
very small. For specific processing conditions, indications of the 25-30 K
transition often seen in thin films were seen in the bulk materials. The lower
temperature transition may be associated with the grain boundaries. These
results indicate that it should be possible to fabricate MgB2 with bulk
properties in in-situ thin films at temperatures of 600 C or less.
