The critical field strength at which a classical domain wall moves through a perfect ferromagnetic crystal of simplified structure is calculated as a function of the ratio between anisotropy energy

and ferromagnetic coupling energy

, taking into account the discrete nature of the spins. When

approaches

intrinsic wall pinning becomes appreciable with critical fields approaching the anisotropy field when

. For

, the wall has a thickness of one atomic distance and thus resembles a ferroelectric wall.