  uch experimental and theoretical efforts have been devoted in the past twenty
years to search for a genuine thermodynamic reentrant phase transition from a
ferromagnetic to either a paramagnetic or spin glass phase in disordered
ferromagnets. So far, no real system or theoretical model of a short-range spin
glass system has been shown to convincingly display such a reentrant
transition. We present here results from Migdal-Kadanoff real-space
renormalization-group calculations that provide for the first time strong
evidence for ferromagnetic to paramagnetic reentrance in Potts spin glasses on
hierarchical lattices. Our results imply that there is no fundamental reason
ruling out thermodynamic reentrant phase transitions in all non mean-field
randomly frustrated systems, and may open the possibility that true reentrance
might occur in some yet to be discovered real randomly frustrated materials.
