The control of the magnetization of a material with an electric field would make the design and the integration of novel electronic devices possible. This explains the renewed interest in multiferroic materials. Progress in this field is currently hampered by the scarcity of the materials available and the smallness of the magnetoelectric effects. Here we present a proofof-principle experiment showing that engineering large strains through nanoscale size reduction is an efficient route for increasing magnetoelectric coefficients by orders of magnitude. The archetype magnetoelectric material, Cr 2 O 3 , in the form of epitaxial clusters, exhibits an unprecedented 600% change in magnetization magnitude under 1 V. Furthermore, a multiferroic phase, with both magnetic and electric spontaneous polarizations, is found in the clusters, while absent in the bulk.

In this paper, the authors focus on two well-identified switching mechanisms, namely, interfacial (or homogeneous) switching and filamentary switching. These switching mechanisms have been reported in various devices, but a broader analysis remains to be conducted. By comparing the performances of TiO2- and HfO2-based resistive switching devices in terms of variability, retention, controllability, and switching energy, the authors discuss how oxygen vacancies organization can determine a general set of properties that will define the range of applications that could be envision for each material/device technology.