Magnetocrystalline and Uniaxial Anisotropy in Electrodeposited Single Crystal Films of Cobalt and Nickel

Abstract

Torque magnetometry was used to determine the uniaxial anisotropy, K _u , observed in addition to the normal magnetocrystalline anisotropy ( K ₁ and K ₂ ) in single crystal f.c.c. Co and Ni films electrodeposited on to (110) Cu single crystal substrates. The easy direction of K _u was found to be the [001] in the film plane and its magnitude at 1000Å was of the order of K ₁ for each material with maximum values of -7.7×10 ⁵ erg cm ^-3 for Co and -3.4×10 ⁵ erg cm ^-3 for Ni occurring at about 150Å at which thickness K ₁ and K ₂ also attained maxima. An empirical relation describing the dependence upon thickness t in angströms is given of the form, \begin{aligned} -K_{u}(\text{erg}\ \text{cm}^{-3}){=}K_{0}\exp(-t/n)+K_{\infty}[1-\exp(-t/100)] \end{aligned} The two terms represent the contributions from strain energy originating in the initial layers and in hydrogen included into the deposit respectively. Measurements of K ₁ , K ₂ and K _u are given for composite layer films which yield unexpected results.