Skyrmion Brownian circuit implemented in continuous ferromagnetic thin film
Résumé
The fabrication of a circuit capable of stabilizing skyrmions is important for the realization of micro- to nano-sized skyrmion devices.
Ultralow power Brownian computers have been theoretically proposed and are a promising example of a skyrmion-based device. However,
such devices have not been realized as it would require skyrmions to be stabilized and easily movable within a circuit. Skyrmion circuits
fabricated by the etching of ferromagnetic films often decrease the dipolar magnetic field stabilizing the skyrmions, thus preventing their
formation. In this study, a skyrmion Brownian circuit has been implemented in a continuous ferromagnetic film with patterned SiO2 capping
to stabilize the skyrmion formation. The patterned SiO2 capping controls the saturation field of the ferromagnetic layer and forms a
wire-shaped skyrmion potential well, which stabilizes skyrmion formation in the circuit. Moreover, using this patterned SiO2 capping, we have
implemented a Y-junction hub circuit exhibiting no pinning site at the junction, contrary to conventional etched hubs. Thus, this technique
enables the efficient control of skyrmion-based memory and logic devices to move closer toward the realization of Brownian computers.