Self-organized spatio-temporal micropatterning in ferromagnetic Co–In films

Cross-sectioning spatio-temporal Co-In electrodeposits: Disclosing a magnetically-patterned nanolaminated structure

“…The HRTEM image (Figure 4c) demonstrates that the material is polycrystalline, in agreement with previous works [28]. It has been claimed that the spatio-temporal structures do move in the vertical direction.…”

“…Indeed, a zoomed detail of the very first layers deposited on the substrate reveals that when an undulation or a "defect" appears, this is conformally wrapped by the subsequent layers until the growing front becomes flattened (Figure 5). Co-In nanolayered films show a ferromagnetic response at room temperature as has been previously reported [28] and shown here in Figure 6. MFM characterization of the cross-section of the deposits was carried in order to assess any kind of magnetic pattering arising from the layer-by-layer architecture of the Co-In films.…”

“…It was also observed that the nanolayers were joined together mostly through In-rich anchor points (see Figures 2b and 2d). Previous EDX mappings conducted on the cross-section of a Co-In deposit seemingly indicated that the distribution of Co and In elements was homogeneous [28]. Current EELS analyses do demonstrate that this is not the case and that composition heterogeneities exist at the nanoscale.…”

“…The spatio-temporal patterns typically consist of a mixture of waves, targets and spirals whose relative proportion was shown to depend on a number of factors, such as the nature of the system and the applied current density. Interestingly, it was recently found that the Co-In system not only exhibits the spatio-temporal selfpattern on the surface, but also a fancy layer-by-layer growth type [28]. Although the spontaneous formation of layered deposits with a repeat length of tens or hundreds of nanometers has been observed in a quite few instances [29][30][31], this growth mode in immiscible systems exhibiting spatio-temporal patterns has not been studied in detail.…”

New examples of electrodeposited alloy systems with pattern formation

“…A possibility for determination of the phase composition of the different elements of the structures offers the electrochemistry, and special the anodic linear sweep voltammetry (ALSV) in combination with X-ray and microscopic observations using the principle, that each phase in the coating has its own dissolution potential in an appropriate electrolyte. [30]). The properties of the cyclic modulated alloy multilayers are investigated depending on the electrolysis conditions and the number and composition of the separate sublayers (AgSb [31], AgBi [32]), as well as the spontaneous formation of multilayers without application of pulsating current is observed (AgSn [13]).…”