Interface stress in Au/Ni multilayers

Abstract

Interdependence of elastic strain and segregation in metallic multilayers: An x-ray diffraction study of (111) Au/Ni multilayers J.The effect of intermixing on the apparent interface stress is studied in ͗111͘-textured dc-magnetron sputtered Au/Ni multilayers by use of two methods commonly used for determining interface stress. The method using profilometry and in-plane x-ray diffraction does not take intermixing into account and yields an apparent interface stress of Ϫ8.46Ϯ0.99 J m Ϫ2 . However, observed discrepancies between model calculations and measured high-angle x-ray diffractograms indicate intermixing, and by use of the profilometry and sin 2 method the real interface stress value of Ϫ2.69Ϯ0.43 J m Ϫ2 is found. This method also reveals a significant and systematic change of the stress-free lattice parameter of both constituents as a function of modulation period which is shown to account for the difference between the two findings. The method using in-plane diffraction is thus shown to be inapplicable to interface stress determinations in systems exhibiting a modulation period-dependent stress-free lattice parameter. Finally, a deviation of the interface stress in the Au/Ni sample with the smallest modulation period as compared to specimens with larger bilayer lengths is observed to be concurrent with a significant decrease in the interface roughness measured by x-ray reflectivity, which suggests that the deviation is of geometrical origin.

Impact of a rubrene buffer layer on the dynamic magnetic behavior of nickel layers on Si(100)

“…These values are much different from the d (111) values of 2.09 Å and 2.06 Å obtained for Ni multilayers grown with different metals such as Au and Co layers, respectively. 51,52 Since the thickness-dependent d (111) values of Ni/rubrene/Si are similar to those of Ni/Si, we used a common approach to estimate the lattice strain ( ε ) in our samples with the relation ε = ( a − a 0 )/ a 0 , where a 0 is the lattice constant of the bulk material and a is the lattice constant calculated from the XRD patterns through . 53–55 The lattice strain ε of the Ni layer experiences a tensile strain of magnitude for 0.96% and compressive strain of 0.31% for Ni(8)/rubrene/Si and Ni(8)/Si, respectively.…”

“…40,50 This suggests that lattice strain of the Ni layer is different for thinner films on a buffered organic layer and a bare Si substrate. 51,52 Since the thicknessdependent d (111) values of Ni/rubrene/Si are similar to those of Ni/Si, we used a common approach to estimate the lattice strain (e) in our samples with the relation e = (a À a 0 )/a 0 , where a 0 is the lattice constant of the bulk material and a is the lattice constant calculated from the XRD patterns through…”

Internal Stress Prediction and Measurement of Mid-Infrared Multilayer Thin Films

“…Spaepen also proposed a method to evaluate the interfacial stress by the curvature method, and showed that the interfacial stress can be tensile or compressive. A number of studies have also used similar methods for the evaluation of interfacial force in multilayer films [ 17 , 18 , 19 ]. However, this method evaluates the average interfacial force of two materials.…”