Electrochemical deposition of iron in a thin cell under an in-plane magnetic field

V. Heresanu^1,2 - R. Ballou¹ - P. Molho¹

¹ Laboratoire Louis Néel, CNRS, BP 166, F-38042 Grenoble cedex 9, France
² Aristotle University of Thessaloniki, Physical Metallurgy Laboratory, Mechanical Engineering Department, Thessaloniki 54006, Greece

Abstract
Complementary experiments were performed to understand a circular to rectangular symmetry breaking of the macroscopic morphology earlier evidenced in a thin cell electrochemical deposition of Fe from Fe(SO₄) aqueous solution under an in-plane magnetic field. Scanning Electron Microscopy shows that the growth is dendritic and that the dendrites get oriented by the magnetic field. In situ optical microscopy during the growth indicates that magnetic dipolar interactions are relevant, modulating the branches orientation. Growths in a quasi-parallel geometry show that the orientation of the branches depends only on the magnetic field, with dendrites closer to the electric field direction growing faster. The rectangular shape is then understood as resulting from the orientation of the dendrites with respect to the magnetic field in order to minimize the Zeeman energy. The branches align at an angle, which should be 60^° from the magnetic field, but modified by dipolar interactions. Figs 6, Refs 9.