Voltage-induced coercivity reduction in nanoporous alloy films: A boost toward energy-efficient magnetic actuation

Magnetic data storage and magnetically actuated devices are conventionally controlled by magnetic fields generated using electric currents. This involves significant power dissipation by Joule heating effect. To optimize energy efficiency, manipulation of magnetic information with lower magnetic fields (i.e., lower electric currents) is desirable. This can be accomplished by reducing the coercivity of the actuated material. Here, a drastic reduction of coercivity is observed at room temperature in thick (≈600 nm), nanoporous, electrodeposited Cu–Ni films by simply subjecting them to the action of an electric field. The effect is due to voltage-induced changes in the magnetic anisotropy. The large surface-area-to-volume ratio and the ultranarrow pore walls of the system allow the whole film, and not only the topmost surface, to effectively contribute to the observed magnetoelectric effect. This waives the stringent “ultrathin-film requirement” from previous studies, where small voltage-driven coercivity variations were reported. This observation expands the already wide range of applications of nanoporous materials (hitherto in areas like energy storage or catalysis) and it opens new paradigms in the fields of spintronics, computation, and magnetic actuation in general.
Financial support by the European Research Council (SPIN-PORICS 2014-Consolidator Grant, Agreement No. 648454), the Spanish Government (Project Nos. MAT2014-57960-C3-1-R and FIS2015-64886-C5-3-P and associated FEDER) and the Generalitat de Catalunya (Nos. 2014-SGR-1015 and 2014-SGR-301) is acknowledged. E.M. acknowledges the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant Agreement No. 665919. E.P. is grateful to MINECO for the “Ramon y Cajal” contract (No. RYC-2012-10839). E.I.-C. acknowledges the grant awarded by the National Council on Science and Technology in Mexico (CONACYT). R.C., R.R., and P.O. acknowledge support from EU H2020-EINFRA-5-2015 MaX Center of Excellence (Grant 676598). The authors would also like to acknowledge networking support by the COST Action e-MINDS MP1407. ICN2 acknowledges the support from the Severo Ochoa Program (MINECO, Grant No. SEV-2013-0295).