2D magnetic domain wall ratchet: The limit of submicrometric holes

In the last decade, magnetic ratchet effect of domain walls has been proposed by several groups as a working principie for spintronic devices like magnetic diodes or shift registers. lndeed, some of the proposed strategies are promising candidates to be seen in the near future in working devices. As an alternative route, we have succeeded in producing and observing magnetic ratchet effects, as well as crossed-ratchet effects, in a ferromagnetic thin film where we have nanopatterned 2D arrays of asymmetric holes in the submicrometric limit for hole sizes. The combination of Kerr microscopy, X-Ray PhotoEmission Electron Microscopy and micromagnetic simulations has allowed a full magnetic characterisation of the domain wall (DW) propagation processes over the whole array and the local DW morphology and pinning at the hales. The simulations also allow to propase a new ratchet/inverted-ratchet effect in the submicrometric range driven by two different mechanisms: magnetic fields and electrical currents.