Structural and Corresponding Magnetic Properties of Sputtered Ni/Al Multilayer Films: Effect of Ni Layer Thickness

Abstract

A series of Ni/Al multilayers with different thicknesses of Ni layers was produced by a sputtering technique. The deposition parameters of optimum magnetic properties for write heads were detected by scanning the magnetic layer thickness from 0 to 70 nm. The optimum magnetic properties were decided by obtaining the saturation magnetization, Ms, coercivity, Hc and Ms/Hc ratios from the hysteresis loops. A face centered cubic (fcc) structure was established for all films. Transition surface morphology; i.e., a surface morphology between an apical + uneven structure (observed for the mono layered Al film) and an acicular + relatively smooth structure (observed for the films with Ni layer thicknesses of 30 nm and 70 nm) occurred on the surface of the film with Ni layer thickness of 10 nm. This transition surface morphology was very similar to that of the substrate as compared to the other morphologies and it may lead to relatively lower Hc value. A significant increase in Hc value was detected for Ni/Al film with Ni layer thickness of 70 nm. The increase was attributed to the irregular acicular morphology of substrate and high crystallite size of Al fcc (111). The deposition parameters of 8[Ni(10 nm)/Al(10 nm)] multilayer can be considered in order to support the higher Ms/Hc ratio which has a key role for effective technological applications of write heads.

Structural properties controlled magnetisation of Ni/Al multilayers sputtered on flexible polymer substrate: Impact of Ni deposition rates

“…The decrease in the H C values of the films can be associated with the decrease in the amount of Al in the film content and, simpler and uniform surface morphologies with the increase in the Ni deposition rate. There are no studies about the magnetic properties of Ni/Al multilayer thin films except for our previous two investigations [16,17]. The saturation magnetisation and coercivity values under study are found to be consistent with these studies.…”

“…According to the results, the Ni contents in the films increased with the increase in Ni deposition rate. The contents of the films show the same trend as the content ratios obtained in the study [16], in which the effects of different layer thicknesses of Ni layers for Ni/Al multilayer films were investigated. As seen in figure 3, with the increase in Ni deposition rate, the peak of the (111) plane of the face-centred cubic (fcc) Al, which is formed at Bragg angle of ∼38.4°.…”

“…As can be clearly seen, the highest M S /H C ratio was obtained in the film where the Ni deposition rate was 0.10 nm s −1 . In our previous study [16], it was emphasized that the M S /H C ratio increased by decreasing the Ni layer thickness and concluded that obtaining Ni/Al multilayer films with a high M S /H C ratio could be achieved with relatively low thickness values. The remanent magnetisation, M r values determined for Ni/Al multilayer films with Ni layer deposition rates of 0.02, 0.04, 0.06, 0.08 and 0.10 nm s −1 were found to be 228.…”

“…The deposition rate is one of the elements influencing the structure of the films in this context [13][14][15]. The effects of various Ni layer thicknesses and Al layer thicknesses on the magnetic characteristics of Ni/Al multilayer films were examined and the findings were described in detail in the studies by Karpuz et al [16] and Kaplan et al [17], respectively. As far as we are aware, no research has been done to examine how the various deposition rates influence the magnetisation of Ni/Al multilayer thin films, which are crucial for magnetic sensors and whose structural characteristics regulate magnetisation.…”

Exploration of the Magnetic Properties of ZrCo:Co Bilayer Films: Effects of the Thickness of the Co Layer on the Anisotropy and Magnetic Interaction Parameters

“…This observation is crucial to understand how the morphology and magnetic properties evolve with layer thickness and preparation conditions. These studies focused in particular on systems based on SmCo, SmFe, FePt, CoFe(Cu), CoFeNi, Fe, or Co. [ 10–20,20–22 ] Films based on the ZrCo alloy represent a significant advance in the field of magnetic materials, due to their application potential in cutting‐edge areas. [ 23–29 ] These films provide a unique platform to study the interactions between different magnetic phases, combining hard and soft magnetic layers.…”