Tools
Tools
Whyte, T. D. (1965) An experimental study of some ferromagnetic properties of electrodeposited single crystal films. Doctoral thesis, Sir John Cass College.
The aim of this present work has been to investigate the conditions for epitaxial growth of electrodeposited single crystal films of nickel and iron on single-crystal substrates and then to measure some magnetic properties of these films and films of β-cobalt. It has been shown by electron diffraction that good single crystal films of nickel and iron can be grown to a thickness of at least one micron on copper and β-brass single-crystal substrates respectively.
The magnetocrystalline anisotropy constants K₁ and K₂ of these films have been studied using torque magnetometer techniques. In the case of nickel films, a variation of K₁ and K₂ with thickness has been found and the results obtained are, in general, higher than the quoted bulk values.
Analysis of the torque curves obtained from all films has shown in addition the presence of a uniaxial component of anisotropy Kᵤ and this was also found to be a function of film thickness. Experiments were made to investigate the variation of anisotropy in nickel deposits prepared from baths maintained at various temperatures and the results are related to stress effects in the films. It has been shown that the effect of {111} twinning in the deposit increases the magnitudes of all the anisotropy constants.
The variation of coercive force with thickness has been measured in electrodeposited polycrystalline films of nickel, iron, α-cobalt and β-cobalt. Similar measurements have been made for the first time on electrodeposited single crystal films of nickel, iron and β-cobalt and it has been found that not only is the coercive force a function of thickness but it is also a function of crystallographic plane and direction within the plane. High values of coercive force have been obtained in thin films, with these values being very much greater than bulk values. An attempt has been made to relate the general variation of coercive force with thickness to various magnetization processes thought to occur in the deposits.
 |
View Item |