Proton-driven ferromagnetic switching of CoO in flexible magneto-ionic cells

Electric-field control of ferromagnetism is demonstrated in a mechanically flexible solid-state system through a proton-induced redox reaction at room temperature. Protons transported through a perfluorosulfonic acid (PFSA) proton exchange membrane (PEM) trigger the reduction of CoO by reacting with...

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Detalhes bibliográficos
Autores: Eiler, Konrad, Tan, Huan, Arredondo-López, Aitor, Solsona, Pau, Pellicer, Eva, Sort, Jordi
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2026
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:dnet:digitalcsic_::f94e239f1201ea592c70cf12998a53f6
Acesso em linha:http://hdl.handle.net/10261/431838
https://api.elsevier.com/content/abstract/scopus_id/105034587137
Access Level:acceso abierto
Palavra-chave:Electrochemical control of magnetism
Flexible magnetoelectric device
Hydrogen magneto-ionics
Magnetic field control of magnetism
Solid-state magneto-ionics
Descrição
Resumo:Electric-field control of ferromagnetism is demonstrated in a mechanically flexible solid-state system through a proton-induced redox reaction at room temperature. Protons transported through a perfluorosulfonic acid (PFSA) proton exchange membrane (PEM) trigger the reduction of CoO by reacting with lattice oxygen, which enables reversible switching between paramagnetic and ferromagnetic states starting at voltages below 10 V. The proton supply is sustained by ambient humidity and water splitting at a Pt thin film counter electrode. Due to its flexibility, the device architecture—a sandwich of CoO and Pt thin films integrated with the polymeric PEM—retains full magneto-ionic functionality under mechanical bending. Three CoO films, synthesised via reactive sputtering under varying conditions, are compared: amorphous, crystalline, and mixed-phase CoO/Co. While the amorphous film exhibits weak response, both the crystalline and mixed-phase films show pronounced electric-field-dependent magnetic switching, highlighting the critical role of microstructure in magneto-ionic performance.