Structural and magnetic properties of Ti/Co multilayers

Abstract

We have investigated the structural and magnetic properties of sputter-deposited Ti/Co multilayer thin films. Sample composition was determined by Rutherford backscattering spectrometry. The crystal structure and composition modulation were examined with several x-ray diffraction techniques. X-ray diffraction analysis showed that the Ti and Co layers grow in the hcp structure and that the films are strongly textured along the (002) direction and are structurally incoherent. Composition modulation was confirmed from low-angle x-ray diffraction measurements. Vibrating-sample magnetometry (VSM) and Brillouin light scattering (BLS) were used to determine the magnetic properties of the films. VSM measurements of samples with Co layer thicknesses less than ≊22 Å showed no measurable net magnetization, while those with greater Co layer thicknesses had both in-plane and perpendicular components. Using a simple model, the measured thickness dependence of the magnetization can be explained by assuming that 11.3 Å of Co at each Ti interface is nonmagnetic with bulk magnetization for the remaining Co. Perpendicular volume and interface anisotropy constants obtained from the VSM data were Ks=0.23 erg/cm2 and Kv=3. 5×106 erg/cm3, respectively. Excellent agreement was obtained between the best fit magnetic parameters for the VSM and the BLS data.