Global random-field spin-glass phase diagrams in two and three dimensions

An Ising model including field randomness and +/-J bond randomness is studied by renormalization-group theory in spatial dimensions d=2 and 3. In d=3, with field randomness but no +/-J randomness, ferromagnetic and paramagnetic phases occur with no intervening spin-glass phase. Also in d=3, at sufficient +/-J randomness, a spin-glass phase occurs, but is replaced by the paramagnetic phase for any nonzero random field, also implying its disappearance for any nonzero uniform field. In d=2, no ferromagnetic phase under random fields and no spin-glass phase occur. Global phase diagrams uniting the random-field and spin-glass problems are evaluated. The strong violation of critical phenomena universality, previously found adjoining random-bond tricriticality in d=3, is seen here in d=2.