Investigation of Ti Layer Thickness Dependent Structural, Magnetic, and Photoemission Study of Nanometer Range Ti/Ni Multilayer Structures

Abstract

Structural, magnetic, and electronic properties of Ti/Ni multilayer (ML) samples as a function of Ti layer thickness are studied and reported in this paper. For this purpose [Ti (t nm)/Ni (5 nm)] x 10 ML samples, where t = 3, 5, and 7 nm have been deposited by using electron beam evaporation technique under UHV conditions at room temperature. Structure of ML samples were determined by using XRD (X-ray diffraction) technique and observed that Titanium is deposited mainly in amorphous nature with FCC structure at lower Ti layer thickness of 3 nm, which transform to crystalline HCP structures above than this Ti layer thickness. Corresponding fitted GIXRR (grazing incidence X-ray reflectivity) patterns shows asymmetric nature of Ti-Ni and Ni-Ti interfaces because of heavy intermixing and interdiffusion of Ni and Ti atoms at Ti-Ni interfaces at lower Ti layer thickness. The depth profiling core level and valence band measurements carried out by using XPS (X-ray photoelectron spectroscopy) technique confirms the interdiffusion and intermixing leading to Ti-Ni alloy phase formation at interfaces during deposition, particularly at lower Ti layer thickness of 3 nm. The corresponding magnetization behavior of ML samples has been investigated using Magneto-Optical Kerr Effect (MOKE) technique and observed that, coercitivity decreases while saturation magnetization increases with Ti layer thickness variations. These results are interpreted and discussed in terms of observed micro-structural changes due to Ti layer thickness vitiations in Ti/Ni multilayer samples.