Randomly placed impurities that alter the local exchange couplings, but do not generate random fields or destroy the long-range order, roughen domain walls in Ising systems for dimensionality 53<d<5. They also pin (localize) the walls in energetically favorable positions. This drastically slows down the kinetics of ordering. The pinned domain wall is a new critical phenomenon governed by a zero-temperature fixed point. For d=2, the critical exponents for domain-wall pinning energies and roughness as a function of length scale are estimated from numerically generated ground states.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)