Growth of fractal electrodeposited aggregates under action of electric and magnetic fields using a modified diffusion-limited aggregation algorithm.
We have simulated the two-dimensional growth of fractal aggregates produced in electrodeposition experiments with axial symmetry in the presence of electric and magnetic fields. A modified diffusion-limited aggregation algorithm based on the Monte Carlo method is used in order to simulate cluster growth under the action of Coulomb and Lorentz forces, taking into account the thermal energy. The ion-particle movement has each step biased by the resultant force; in the algorithm, it is mediated by the Boltzmann term. The electric voltage between the electrodes tends to compact the aggregates and reduce the effect of screening. The Lorentz force provides a spiral form for aggregates which twists according to the magnetic field direction and intensity. A function was defined to measure the chirality of the system. The fractal dimension was also calculated to measure the influence of the electric and magnetic fields as well as the temperature during the growth process. Good agreement with experimental results was observed.
Cronemberger
Carolina M
CM
Centro Brasileiro de Pesquisas Físicas (CBPF/MCT), Rua Dr Xavier Sigaud 150, URCA, Rio de Janeiro 22290-180, Brazil. carolina@cbpf.br
Sampaio
Luiz C
LC