Tunable Quantum Tunneling of Magnetic Domain Walls
  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. 
J. Brooke, T. F. Rosenbaum, and G. Aeppli