Control of crystal orientation in zinc electrodeposits by imposition of a high magnetic field

The control of crystal orientation by the imposition of a high magnetic field is discussed from the viewpoint of magnetization energy. The effect of a magnetic field on crystal orientation of zinc electrodeposits was evaluated by the use of orientation indices calculated from the relative intensities of X-ray diffraction peaks. When the magnetic field was imposed perpendicularly to the cathode substrate plane, the observed orientation plane of zinc electrodeposits was the c-plane of a crystal cell, which agrees with a theoretical prediction based on the magnetization energy. The orientation indices of the c-plane increased with the increase in the imposed magnetic field. On the other hand, when the direction of the magnetic field was parallel to the cathode substrate plane, the observed orientation plane was not the a- and b-planes as would be expected based on the theoretical prediction, but remained the c-piane. This discrepancy between the theoretical and the experimental results is due to the decrease in the overpotential generated by the how in the electrolyte solution caused by the Lorentz force. This force is inevitably induced when an electric field and a magnetic field are applied perpendicularly each other.