Magnetic-domain-wall AC dynamics in ultrathin ferromagnetic films

DOMENICHINI, P.; PARIS, F.; QUINTEROS, C. P.; GRANADA, M.; GEORGE, J.-M.; CURIALE, J.; BUSTINGORRY, S.; KOLTON, A. B.; CAPELUTO, M. G.; PASQUINI, G.

San Carlos de Barilche

Workshop; International Workshop on Spintronics (SPIN Argentina 2022); 2022

The dynamics of domain walls (DWs) under external magnetic fields reveals a complexbehavior where sample disorder plays a key role. Furthermore, the response to alternating (AC)magnetic fields has only been explored in limited cases and analyzed in terms of the constantfield solution acting on interfaces that are flat on average. Here we present results obtained bymagneto-optical imaging the evolution of magnetic DWs in ultrathin ferromagnetic films withperpendicular anisotropy, under the application of AC magnetic fields within the creep regime.Whereas the DC characterization is well predicted by an elastic flat interface model,unexpected features are observed under the application of alternating square pulses in bubblemicrometer-sized magnetic domains [1]: We show that under a zero bias AC field there is astriking bubble area reduction, concomitant with a roughness domain wall increase, withfurther evolution to strongly distorted shapes. We propose an analytical model [2], based onthe curvature induced symmetry breaking, able to quantitatively explain the intriguing“rectification effect”. Numerical simulations, able to reproduce the experimental observations,support the analytical model. A qualitative explanation of the enhancement of large scaledynamic roughening is also proposed. References[1] P. Domenichini, C. P. Quinteros, M. Granada, S. Collin, J.-M. George, J. Curiale, S. Bustingorry, M. G.Capeluto, and G. Pasquini, Phys. Rev. B 99, 214401 (2019).[2] P. Domenichini, F. Paris, M. G. Capeluto, M. Granada, J.-M. George, G. Pasquini and A. B. Kolton, Phys.Rev. B 103, L220409 (2021).