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Item Magnetic properties of Fe56Pd44−xGdx thin films(American Institute of Physics, 2024) Sahari, Mohamed Abdennour; Olivetti, Elena Sonia; Magni, Alessandro; Fiore, Gianluca; Boudissa, Mokhtar; Tiberto, Paola; Bahamida, Saida; Coïsson, MarcoIn this paper, we have studied the effect on the structure and magnetic properties of partial Pd substitution by Gd in Fe-Pd thin films of nominal composition Fe56Pd44−xGdx (x = 1, 3, 5, and 7), deposited onto Si(100) and Si(100)/SiO2 substrates by thermal evaporation. Several techniques contribute to the characterization of their microstructure and magnetic properties, such as x-ray diffraction (XRD), scanning electron microscopy, alternating gradient field magnetometry, and magnetic force microscopy (MFM). X-ray diffraction shows that the as-deposited films are either amorphous or contain a disordered FePd phase, depending on the film thickness. The transformation of disordered fcc-FePd into ordered fct-FePd has been induced by a heat treatment at 530 °C for 4 h. The addition of gadolinium leads to a reduction in the coercivity as a consequence of the emergence of soft phases and of the progressive reduction of the fct-FePd phase, which is primarily responsible for the observed maze magnetic domains. The exchange coupling between the soft phase and the hard fct-FePd phase is demonstrated by first-order reversal curves (FORCs).Item Impact of substrate on the formation mechanism of electrodeposited Co–Ni thin films: a comprehensive study of structural, morphological, and magnetic properties(Springer, 2024) Boulegane, Ala; Guittoum, Abderrahim; Hadj Larbi, Abderrahim; Laggoun, Ali; Boudissa, MokhtarIn this work, we investigated the effect of substrate on the structural, morphological, and magnetic properties of electrodeposited CoNi thin films from a chloride bath. Three samples of CoNi films were deposited at room temperature onto different substrates: FTO, ITO, and Cu. Electrochemical studies were performed using cyclic voltammetry experiments. Energy-dispersive X-ray spectroscopy (EDX) showed that all the samples had a cobalt content of more than 80%. X-ray diffraction (XRD) spectra revealed that the films deposited on Cu had a face-centered cubic (FCC) phase, while those deposited on ITO and FTO had a mixture of hexagonal close-packed (HCP) and FCC phases. The lattice parameter (a) and crystallite size (D) were strongly dependent on the substrate. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe the morphology of the films. All the samples had a granular morphology with spherical grains, but the roughness and surface distribution varied with the substrate. The magnetic properties of the films, such as coercivity (Hc) and squareness (S), were investigated using a vibrating sample magnetometer (VSM). The results showed that Hc and S were both affected by the substrate and the film composition. Overall, our results showed that the substrate had a significant effect on the structural, morphological, and magnetic properties of electrodeposited CoNi thin films. These findings could be used to design and optimize CoNi thin films for specific applications.Item Structural, morphological, and magnetic properties of electrodeposited coNi thin films on the FTO substrate(Springer, 2022) Boulegane, Ala; Guittoum, Abderrahim; Laggoun, Ali; Boudissa, Mokhtar; Hemmous, MessaoudCoNi films were elaborated by electrodeposition onto FTO substrates using a chloride bath with a metallic ion molar ratio [Co2+]/[Ni2+] equals 1/1. Three samples were elaborated for different potentials ranging from −1.6 to −1.5 V. The structure and the morphology of CoNi films were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The chemical compositions are obtained using energy dispersive X-ray (EDX) and the magnetic properties were studied using a vibrating sample magnetometer (VSM). From X-ray diffraction, we have shown the presence of the FCC phase of CoNi binary alloy with a well-pronounced texture along the < 111 > , < 200 > , and < 220 > planes for all samples. We have found that the applied potential has an influence on crystallite sizes. Besides, a moderate change in the lattice parameter has been observed with increasing applied potential. The AFM images show that the applied potential changes the morphology and the surface roughness of CoNi films. In addition, the SEM images confirm the granular morphology of CoNi deposits and show a good relationship between voltage and grain size. The EDX spectrums confirm the deposition of the cobalt and the nickel on the FTO substrate and show the precedence deposition of Co compared with Ni. The extracted coercive field Hc and squareness from the hysteresis loops explained the good correlation between the magnetic and structural properties of CoNi thin filmsItem Magnetic properties of bcc and bcc-fcc Fe-Pd alloys produce by thermal evaporation technique(Elsevier, 2014) Bahamida, Saida; Laggoun, Ali; Guittoum, Abderrahim; Fnidiki, Abeslem; Boudissa, MokhtarItem Structural and mössbauer studies of evaporated Fe100-xPdx thin films(EDP Sciences, 2014) Laggoun, Ali; Guittoum, Abderrahim; Bahamida, Saida; Boudissa, Mokhtar; Fnidiki, AbdesslemIn order to study the influence of palladium atom on structural and hyperfine properties, Fe100-xPdx films (x = 15, 20 and 36 at.%) were deposited by evaporation method onto a Si (1 0 0) substrate. They were then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and conversion electron Mössbauer spectroscopy (CEMS). X-ray diffraction analysis shows the presence of supersaturated solid solution with bcc structure for Pd concentration of 15% and 20%. However, for 36% of Pd, in addition to the supersaturated α-FePd (bcc) phase, another disordered FePd3 phase with fcc structure is present. The grain size did not change with Pd concentration and was about 11 nm, and the lattice parameter increased from 0.287 Å to 0.290 Å with an increasing Pd concentration. The adjustment of Mössbauer spectra confirms the results obtained by X-ray diffraction. Moreover, the Mössbauer spectra have shown that a magnetic texture is present for samples with 20 and 36%. For these Pd concentrations, we believe that a development of an out-of plane magnetic anisotropy occurs in our films