Tunable Magnetism in Nanoporous CuNi Alloys by Reversible Voltage‐Driven Element‐Selective Redox Processes. Issue 21 (18th April 2018)

• Record Type: Journal Article
• Authors: Quintana, Alberto; Menéndez, Enric; Isarain‐Chávez, Eloy; Fornell, Jordina; Solsona, Pau; Fauth, François; Baró, Maria Dolors; Nogués, Josep; Pellicer, Eva; Sort, Jordi
• Is Part Of: Small. Volume 14:Issue 21(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-04-18
• Subjects: magneto‐electric effects -- nanoporous alloys -- redox processes; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201704396
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Voltage‐driven manipulation of magnetism in electrodeposited 200 nm thick nanoporous single‐phase solid solution Cu20 Ni80 (at%) alloy films (with sub 10 nm pore size) is accomplished by controlled reduction‐oxidation (i.e., redox) processes in a protic solvent, namely 1m NaOH aqueous solution. Owing to the selectivity of the electrochemical processes, the oxidation of the CuNi film mainly occurs on the Cu counterpart of the solid solution, resulting in a Ni‐enriched alloy. As a consequence, the magnetic moment at saturation significantly increases (up to 33% enhancement with respect to the as‐prepared sample), while only slight changes in coercivity are observed. Conversely, the reduction process brings Cu back to its metallic state and, remarkably, it becomes alloyed to Ni again. The reported phenomenon is fully reversible, thus allowing for the precise adjustment of the magnetic properties of this system through the sign and amplitude of the applied voltage. Abstract : The magnetic properties of the nanoporous Cu20 Ni80 electrodeposited films can be reversibly tuned using a voltage‐driven electrochemical approach in an aqueous electrolyte (via controlled electrochemical redox processes). The element selectivity of the oxidation process allows for a strong enhancement of the magnetic moment upon application of positive voltages. The effect is fully reversible by changing the sign of the applied voltage.