Magnetic domain wall tunneling is observed in the disordered Ising ferromagnet LiHo_{0.44}Y_{0.56}F_4. The tunneling can be tuned by applying a magnetic field transverse to the Ising axis, and is readily modeled with a WKB formalism.
@article{arxiv.cond-mat/0202361,
title = {Tunable Quantum Tunneling of Magnetic Domain Walls},
author = {J. Brooke and T. F. Rosenbaum and G. Aeppli},
journal= {arXiv preprint arXiv:cond-mat/0202361},
year = {2015}
}