Aleix Barrera

1 Introduction Progress in materials science is closely linked to the development of novel experimental capabilities able to address relevant open questions. In particular, research areas such as, spintronics [1-3], topological magnetism [4, 5], magnetization dynamics [6], multiferroics [7] and nanomagnetism [8] demand spatially resolved and magnetically sensitive techniques capable of visualizing spin textures and magnetic domains as a function of an externally applied magnetic field [9, 10].

Abstract Rapid progress in information technologies has spurred the need for innovative memory concepts, for which advanced data-processing methods and tailor-made materials are required. Here we introduce a previously unexplored nanoscale magnetic object: an analog magnetic vortex controlled by electric-field-induced ion motion, termed magneto-ionic vortex or “vortion”. This state arises from paramagnetic FeCoN through voltage gating and gradual N3– ion extraction within patterned nanodots.