Magneto-optical imaging of AC and DC domain walls dynamics in Pt/Co/Pt ultrathin films

P. DOMENICHINI; C. QUINTEROS; M. GRANADA; J. CURIALE; M. G. CAPELUTO; G. PASQUINI

San Carlos de Bariloche

Simposio; SLAFES XXIII; 2018

The dynamics of domain walls (DW) in ultra-thin ferromagnetic films received much attention in recent years because of its potential application in the area of spintronics. Beside the practical implications, from the basic point of view, DW in thin films with perpendicular magnetic anisotropy (PMA) are particularly interesting, because its motion can be modeled as an elastic interface driven in the presence of weak disorder [1,2]. In the last decade, several experimental and theoretical works explained the main results in term of different steady DC regimes [1,2], but until now there are just a few studies exploring the AC DW dynamics [3]. The magneto-optical (MO) microscopy is one of the most versatile techniques to image the dynamic of magnetic domains in ferromagnetic films [1,2,3]. The method is based on the MO Kerr (or Faraday) effect, i.e. the rotation of linearly polarized light in dependence of the local magnetization direction on reflection (or transmission) from the sample. This work includes the design and construction of a home made MO Kerr microscope in the Physics Department, FCEyN, UBA. We study the dynamics of domain wall in ultrathin Pt/Co/Pt films with PMA under the action of different DC and AC fields. The films where grown in the RMN Laboratory, CAB, CNEA, using layer-by-layer evaporation steps. The characteristic curves of velocity and the mean displacement are analyzed and compared, revealing characteristic features of the oscillatory DW dynamics.