2ND-ORDER PHASE-TRANSITION IN CRYSTALS WITH LONG-RANGE CORRELATED QUENCHED DEFECTS

We consider the phase transition in a ferromagnet with line defects th at introduce a local variation of the critical temperature V(r)proport ional to r(perpendicular to)(-Delta), leading to a correlator [V(O)V(R )]proportional to r(perpendicular to)(-(2 Delta-d)). We discuss condit ions of both local and global character that lead to different scenari os for the transition, ranging from a ''conventional'' transition into a homogeneous phase that can be described within the framework of the standard renormalization group to a transition into an inhomogeneous phase with a percolating network of ordered regions.