  We consider a model where the strong magnetic fields of magnetars arise from
a high baryon density, magnetized core. In this framework magnetars are
distinguished from pulsars by their higher masses and central density. For
magnetars, as core densities exceed a threshold, the strong interaction induces
a phase transition to a neutral pion condensate that aligns all magnetic
moments. The core magnetic field is initially shielded by the ambient high
conductivity plasma. With time the shielding currents dissipate transporting
the core field out, first to the crust and then breaking through the crust to
the surface of the star. Recent observations provide strong support for this
model which accounts for several properties of magnetars and also enables us to
identify new magnetars.
