Microstructure and magnetic properties of Fe/Ti multilayers

Abstract

The microstructure and magnetic properties of Fe/Ti multilayer films prepared by rf-sputtering deposition are studied via conversion electron Mössbauer spectroscopy (CEMS), x-ray diffraction (XRD), and magnetic techniques. Samples with the two Ti-to-Fe thickness ratios β = 1 and β = 1.5, and with modulation wavelengths of 5 to 80 nm were studied. The XRD, electrical conductivity and coercive-field measurements revealed that the amorphous phase is formed during depostion and is distributed in the plane between the crystalline sublayers as well as in the grain boundaries. From CEMS measurements the relative fractions of the various phases (α-Fe, the interfacial FeTi crystalline phase and the amorphous phase) were determined. The thickness of the mixed interfacial region was estimated for various values of A and β. The CEM spectra revealed that the spins in the Fe sublayers are aligned in the plane of the film, while in the interfacial regions they are randomly oriented. It is shown that the films with A = 5 nm are almost entirely amorphous. The relative fraction of the amorphous phase decreases dramatically with increasing A.