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 pas t 20 years to searching for a genuine thermodynamic reentrant phase tr ansition from a ferromagnetic to either a paramagnetic or spin-glass p hase 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 M igdal-Kadanoff real-space renormalization-group calculations that prov ide strong evidence for ferromagnetic to paramagnetic reentrance in Po tts spin glasses on hierarchical lattices. Our results imply that ther e is no fundamental reason to rule out thermodynamic reentrant phase t ransitions in all non-mean-field randomly frustrated systems, and may open the possibility that true reentrance might occur in some yet to b e discovered real randomly frustrated materials. [S0163-1829(98)06217- 1].