Spontaneous formation of spiral-like patterns with distinct periodic physical properties by confined electrodeposition of Co-In disks

Abstract

Spatio-temporal patterns are ubiquitous in different areas of materials science and biological systems. However, typically the motifs in these types of systems present a random distribution with many possible different structures. Herein, we demonstrate that controlled spatio-temporal patterns, with reproducible spiral-like shapes, can be obtained by electrodeposition of Co-In alloys inside a confined circular geometry (i.e., in disks that are commensurate with the typical size of the spatio-temporal features). These patterns are mainly of compositional nature, i.e., with virtually no topographic features. Interestingly, the local changes in composition lead to a periodic modulation of the physical (electric, magnetic and mechanical) properties. Namely, the Co-rich areas show higher saturation magnetization and electrical conductivity and are mechanically harder than the In-rich ones. Thus, this work reveals that confined electrodeposition of this binary system constitutes an effective procedure to attain template-free magnetic, electric and mechanical surface patterning with specific and reproducible shapes.

Depth-Dependent Scanning Photoelectron Microspectroscopy Unravels the Mechanism of Dynamic Pattern Formation in Alloy Electrodeposition

“…Notwithstanding the large corpus of systems investigated, recently reviewed in Bozzini et al and Krastev et al, still the mechanisms governing the spatiotemporal organization during electrochemical phase formation are poorly understood. Electrodeposition studies (for a comprehensive list of references, see Bozzini et al) have initially dealt with a range of Ag alloys (Ag–Sb, Ag–Sn, Ag–In, Ag–Bi, Ag–Cd), but it has been recently shown that similar phenomena also occur with Bi, In and Sb alloys not involving Ag: Ni–P–W–Bi, Au–In, Co–In, , Pd–In, Cu–Sb . Moreover, alloys with Pt-group metals, as Ir–Ru and Pt–Ir, electrodeposited from molten salts, have been found to exhibit the same type of dynamic behavior.…”

Unexpected Downstream Mode of Spatiotemporal Rotating Waves Found in the Model of H2O2 Reduction on a Platinum Ring-Shaped Electrode under Mild Convection

“…There are the strong relationships between the pattern structure and the experimental conditions such as the applied potential, concentration of chemicals, and type of complex agents . Also, recent studies experimentally show that the spatiotemporal patterns emerge on microdiscs and spherical electrodes as well as mm-sized flat electrodes. Therefore, the self-organization process is versatile in terms of the controllability of the material structure and the abundant choice of the substrate.…”

Influence of the Ligands in Cu(II) Complexes on the Oscillatory Electrodeposition of Cu/Cu2O

“…The synthesis of materials with novel physicochemical properties employing the controlled manipulation of their microstructure at the atomic level became a field based on solid-state chemistry. , As recently proposed, nevertheless, self-organization under far from equilibrium conditions can also be utilized as a promising and alternative synthetic method to create more complex materials in terms of structure and composition. − Differently from a standard step-by-step synthesis procedure, self-organized electrochemical structures arise without any external control or template-based support . Nanostructured metallic multilayers, magnetic nanopatterning, switchable roughness surfaces, and porous nanoarrays are a few examples found through the use of this nonequilibrium synthetic method. Followed by the spontaneous assembly of the material constituents, temporal instabilities, such as excitability, multistability, and oscillations, are observed on the main variables that describe the system .…”

“…3−7 Differently from a standard step-by-step synthesis procedure, self-organized electrochemical structures arise without any external control or template-based support. 8 Nanostructured metallic multilayers, 9 magnetic nanopatterning, 10 switchable roughness surfaces, 11 and porous nanoarrays 12 are a few examples found through the use of this nonequilibrium synthetic method. Followed by the spontaneous assembly of the material constituents, temporal instabilities, such as excitability, multistability, and oscillations, are observed on the main variables that describe the system.…”