Magnetic force microscopy characterization of core–shell cobalt-oxide/hydroxide nanoparticles

Cobalt-based nanoparticles directly synthesized on conductive substrates through electrodeposition find application in a broad range of scientific and technological fields.The capability to characterize both morphological parameters (e.g., shape, size, structure, and numerical density per unit of area) and magnetic properties (e.g., magnetic moment, saturation magnetization, or coercivity) directly on the substrate on which they are grown is fundamental for many of those applications. In this work, we report on the use of magnetic force microscopy (MFM) to characterize Co-based nanoparticles synthesized through electrodeposition on Al substrates using two different counter electrodes, i.e., Co and Pt. Morphological analysis using AFM and scanning electron microscopy (SEM) was used to assess differences in size and number density of the nanoparticles obtained using the two counter electrodes, while MFM was employed to measure the remanent magnetization of single isolated nanoparticles, to asses the presence of a nonmagnetic shell on the nanoparticles and to estimate their thickness.