Characterization of microstructural and morphological properties in as-deposited Ta/NiFe/IrMn/CoFe/Ta multilayer system

Abstract

Surface morphology and its relationship with microstructure in Ta/NiFe/IrMn/CoFe/Ta multilayer system deposited by pulsed DC magnetron sputtering have been investigated in dependence of Ta buffer and NiFe seed layer thicknesses using atomic force microscopy. The structural parameters such as grain size, dislocation density, texture and strain were calculated. For each surface, a self-affinity behavior with mean fractal dimensions in the range of 2.03-2.18 was found. Additionally, it was also observed that the surface of all samples has locally smooth textured surface structure in the short range. The texture aspect parameter and texture direction index have been obtained for isotropy/anisotropy surface texture. A significant relationship between the surface texture and the strength of the <111> texture in IrMn layer has been found. The analysis indicated that the surface roughness is strongly affected by the thicknesses of the NiFe seed and Ta buffer layers.