  We report that Sb2Te, a natural superlattice phase consisting of two
elemental Sb2 layers interleaved with single Sb2Te3 layers, becomes
ferromagnetic at low temperatures on doping with small percentages of Mn.
Ferromagnetism appears for Mn concentrations as low as Sb1.98Mn0.02Te, where a
ferromagnetic Tc of ~ 8.6 K is observed. Tc decreases with increasing Mn
content in the stoichiometric materials but increases with increasing Te excess
in materials of the type Sb1.93-yMn0.07Te1+y, starting at ~ 3 K at y = 0 and
reaching a Tc of ~ 8.9 K at y = 0.06.
