Domain walls subject to quenched impurities (invited)

Interfaces between domains become rough as a result of pinning to impurities. The degree of roughening can be characterized by the exponent describing the scaling of fluctations with the size of the domain wall. Current understanding of the roughening process will be reviewed. The simple Imry–Ma scaling arguments are expected to give the correct roughening exponent in systems subject to random-field impurities, but they clearly fail in the case of random bonds. Possible reasons for this failure are examined. A novel class of impurities, with long-range power-law interactions with the interface, are considered. By changing the exponent of the power law, this model interpolates between random bonds and random fields.