Pinning of a Bloch point by an atomic lattice

TL;DR

This paper investigates how the atomic lattice's discrete structure creates a periodic potential that can pin Bloch points in magnetic materials, affecting their depinning forces and fields.

Contribution

It introduces the concept that the atomic lattice's discreteness can pin Bloch points and quantifies the resulting pinning forces and depinning fields.

Findings

Pinning force is on the order of the exchange constant.

Depinning field can reach tens of oersted.

Atomic lattice discreteness influences Bloch point dynamics.

Abstract

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 oersted.