Variation of the magnetic properties of electrodeposited Ni and Co nanowire arrays in crystalline and amorphous alumina membranes

Abstract This study investigates the magnetic properties of Ni and Co nanowire (NW) arrays at room temperature, embedded in porous anodic aluminum oxide (Al 2 O 3 ) membranes exhibiting amorphous and γ crystalline phases. Characterizing the Al 2 O 3 membrane morphology has revealed increased nanopore roughness and the appearance of mesopores within their walls with Al 2 O 3 crystallization. As a result of these morphological changes, the morphology of the NWs is also modified, increasing their surface roughness due to the inverse replication of the membrane during the electrodeposition process. Ferromagnetic resonance experiments reveal that the magnetic anisotropy of Ni NWs in amorphous Al 2 O 3 is the result of the superposition of magnetostatic (MS) and magnetoelastic contributions, while Ni NWs in crystalline Al 2 O 3 exhibit only the MS contribution, highlighting the host membrane influence on the NW magnetic behavior. In contrast, Co NW arrays exhibit purely MS behavior across all membranes. The present results are of prime interest for developing magnetic nanocomposites with tunable properties for advanced spintronic and magnetic sensing applications.