Evidence for a genuine ferromagnetic to paramagnetic reentrant phase transition in a Potts spin-glass model

Many experimental and theoretical efforts have been devoted in the past 20 years to searching 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 convincingly to display such a reentrant transition. We present here results from Migdal-Kadanoff real-space renormalization-group calculations that provide strong evidence for ferromagnetic to paramagnetic reentrance in Potts spin glasses on hierarchical lattices. Our results imply that there is no fundamental reason to rule 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. [S0163-1829(98)06217-1].