Total film thickness controlled structural and related magnetic properties of sputtered Ni/Cu multilayer thin films

9th Joint European Magnetic Symposia (JEMS) -- SEP 03-07, 2018 -- Mainz, GERMANYWOS:000458776900008In this study, the impact of total film thicknesses on the structural and magnetic properties of multilayers was investigated. The multilayer films were produced by a DC magnetron sputtering system by considering different total thickness values as x[Ni(10 nm)/Cu(30 nm)] (x = 3, 6, 7). A face centered cubic crystalline structure with (111) preferential orientation was formed for all Ni/Cu multilayers investigated. The number of grains on surface immensely increased and their size significantly decreased as the total film thickness was systematically increased. And also, the arithmetic mean roughness deviation (Ra) and root mean square (Rq) values increased with the increase of total thickness of Ni/Cu films. From scanning electron microscope and atomic force microscope results, the surface roughness increased with increasing the total thickness. The saturation magnetization (M-s), remanent magnetization (M-r) and coercivity (H-c) values were also measured. The M-s values increased from 590 emu/cm(3) to 615 emu/cm(3), M-r values decreased from 396 emu/cm(3) to 204 emu/cm(3) and H-c values gradually decreased from 116 Oe to 89 Oe as the total film thickness increased from 120 nm to 280 nm. It was found that total thickness of Ni/Cu multilayers is an effective parameter and has a considerable role to adjust the magnetic properties for the intended purposes.Scientific Research Fund of Balikesir University/Turkey [2015/195]; State Planning Organization/TurkeyTurkiye Cumhuriyeti Kalkinma Bakanligi [2005K120170]This study was financially supported by the Scientific Research Fund of Balikesir University/Turkey under grant number of 2015/195 and by the State Planning Organization/Turkey under grant number of 2005K120170 for Sputtering and VSM systems. The authors would like to thank to the Bilkent University/Turkey - UNAM, Institute of Materials Science and Nanotechnology for EDX, XRD measurements and SEM images, to the Karamanoglu Mehmetbey University for AFM imaging, to Prof. H. Guler (Balikesir University) for his help in XRD preliminary measurements

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

WOS:000459747100015A 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, M-s, coercivity, H-c and M-s/H-c 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 H-c value. A significant increase in H-c 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 M-s/H-c ratio which has a key role for effective technological applications of write heads.Karamanoglu Mehmetbey UniversityKaramanoglu Mehmetbey University [17-M-15]; State Planning Organization/TurkeyTurkiye Cumhuriyeti Kalkinma Bakanligi [2005K120170]This study was financially supported by the Karamanoglu Mehmetbey University under Grant no 17-M-15, and by the State Planning Organization/Turkey under Grant no. 2005K120170 for Sputtering and the VSM systems. The authors would like to thank Hilal Kuru and Mehmet Uckun for their contributions during the film production and measurements. The authors are also grateful to the Karamanoglu Mehmetbey University/Karaman for the AFM imaging and the XRD measurements, and Selcuk University/Konya for the EDX measurements and the SEM images

Magnetic properties affected by structural properties of sputtered Ni/Cu multilayer films with different thicknesses of Ni layers

WOS:000745596600011Nickel-containing magnetic films have become the focus of attention due to their outstanding properties. These films are produced by many methods, including the sputtering technique. In this study, structural and magnetic properties of Ni/Cu multilayer films with different (from 92.5 nm to 17.5 nm) thicknesses of the Ni layers were investigated. The magnetron sputtering process was used to produce the Ni/Cu multilayer films. X-ray diffraction analysis showed that the films have a face-centered cubic structure with (111) plane. According to the scanning electron microscope images, while the films with the Ni layers thicknesses of 92.5 nm and 42.5 nm have some cracks and row structures on their surfaces, the films with lower thicknesses of the Ni layers have relatively more regular surfaces. As the Ni layers thickness decreased, the saturation magnetization (Ms) decreased from 617 emu/cm3 to 387 emu/cm3. Although the Ni/Cu multilayer with the Ni layer thickness of 92.5 nm had the highest atomic Ni content (76%); its coercivity (Hc) value was also the highest with 144 Oe. There was a decrease in the Hc value and grain size with decreasing the Ni layer thickness and the change in the Hc value can be related to the film content and surface morphology. The remanent magnetization (Mr) value changed between 492 emu/cm3 and 105 emu/cm3 with the reducing the Ni layers thickness. The highest Mr value and the highest Mr/Ms ratio were obtained for the Ni/Cu film with the Ni layers thickness of 42.5 nm. This Ni/Cu film has also the highest magnetization energy. The detected magnetic properties make this film desirable for permanent magnet and magnetic recording applications among the investigated Ni/Cu multilayers

Evaluation of properties of sputtered Ni/Cu films with different thicknesses of the Cu layer

WOS:000645443100004In this study, Ni/Cu thin films with Cu layer thicknesses varying from 200 nm to absence of Cu (0 nm) were produced by using a magnetron sputtering technique in order to investigate their structural and magnetic properties. The X-ray diffraction analysis showed that the films deposited had a face-centered cubic structure and their crystallization was preferably oriented at the (111) plane. In addition, as the Cu layer thickness decreased from 200 nm to 0 nm, the intensity of fundamental Cu (111) decreased while the intensities of Ni (111) and Ni (200) increased. According to surface analysis, although pure Cu film had some specific and clear structures that were nearly spherical in form and varied in size on the surface, the film with a Cu layer thickness of 90 nm had some dark spots on the surface. The saturation magnetization (Ms) values increased with the increase of the Ni content of the films as the Cu layer thicknesses gradually decreased. Conversely, while the Cu content reduced with decreasing Cu layer thicknesses, the coercivity (Hc) values also decreased, except for the film with Cu layers thickness of 90 nm. It is possible that the dark spots seen in the scanning electron microscope image may have lowered the Hc value for the film with a Cu layer thickness of 90 nm. Thus, the production parameters of the film with a Cu layer thickness of 90 nm are optimal for obtaining multilayer films with a lower Hc value. Also, the parameters of the Ni/Cu multilayers with a Cu layer thickness of 15 nm can be considered to achieve a relatively high Ms value. In conclusion, changes in the Cu layer thickness can lead to significant alterations in the microstructural and therefore the magnetic properties