Pinning of a Bloch point by an atomic lattice

Bloch points are magnetic topological defects. The discrete nature of a magnetic lattice creates a periodic potential that can pin a Bloch point. The pinning force is of the order of the exchange constant, a few piconewtons in a typical ferromagnet (permalloy). A domain wall containing a Bloch point can have a sizable depinning field in the tens of oersteds.