Geometry-Induced Domain Wall Pinning in the Exchange Spring Heterostructures of Soft Magnet Fe3Pt and Hard Magnet FePt

Geometry-induced domain wall pinning has been studied in heterostructure with soft magnet Fe3Pt and hard magnet FePt. It is demonstrated that the domain wall is pinned at the interface region of the Fe3Pt/FePt heterostructure under a small current field owing to the spin-transfer torque. The pinning of the domain wall is strongly dependent on the geometry of both soft and hard magnets. The thickness of the heterostructure Fe3Pt/FePt has an important influence on the pinning of the domain wall, which is caused by the combined effects of demagnetization, exchange coupling, and anisotropy. Moreover, with an increase in the width of the hard magnet FePt, the current of the pinning domain wall increases. With an increase in the width of the soft magnet, Fe3Pt, the pinning current decreased to a minimum value and then increased. These results are helpful for the fabrication and design of magnetic storage devices.

Automated summary

This study investigates the influence of geometry on the pinning of domain walls in magnetic materials. The experiments demonstrate that the domain wall can be pinned at the interface region of the Fe3Pt/FePt heterostructure under a small current field, and the pinning is strongly affected by the geometry of both soft and hard magnets. Moreover, the thickness of the heterostructure has an important impact on the pinning, and increasing the width of the hard magnet increases the current required for pinning, while increasing the width of the soft magnet first decreases and then increases the pinning current.