Electric-field-induced diffusion-limited aggregation (EDLA) fractals formed by the suspended metal microspheres in an oil are observed experimentally. The formation of an EDLA fractal is due to the interaction of the dipole-dipole force induced on the metal microspheres when these microspheres are presented in an external electric field. The EDLA fractal grows as the applied field strength is slowly increased. At a fixed volume fraction φ, the dimensions ${\mathrm{D}}_{\mathrm{f}}$ of all fractals formed under the different space fields are in the range of 1.72±0.1. We find that the fractal dimension ${\mathrm{D}}_{\mathrm{f}}$ changes as the volume fraction φ of metal particles varies and satisfies the relationship of ${\mathrm{D}}_{\mathrm{f}}$∼${\mathrm{\phi }}^{\mathrm{m}}$, where m is approximately 1.52.

• Received 25 November 1996

DOI:https://doi.org/10.1103/PhysRevE.55.R2100