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    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, Marco
    In 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).
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    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, Mokhtar
    In 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.
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    Characterization and tribological properties of W-Ti-N/Al-Si multilayer surface coating for iron alloy pistons
    (Springer, 2021) Chemaa, Khaled; Hassani, Salim; Gaceb, Mohamed
    Piston skirts undergo important wear and abrasion due to poor tribological properties. A surface coating system with appropriate friction and hardness properties is proposed in this work to enhance the base material durability of iron alloy pistons. Aluminum-Silicon (Al-Si) thin film was deposited using vacuum evaporation process from 85 at.% Al and 15 at.% Si powders. The W-Ti-N thin film was deposited on the top of the Al-Si thin film using a PVD sputtering process from a W-Ti (70 at.% W and 30 at.% Ti) target onto a stainless steel substrate. The microstructural, mechanical and tribological properties of the multilayer were studied for potential applications on piston skirts manufactured from iron alloys. W-Ti-N/Al-Si multilayer shows a dense microstructure morphology with W2N (200) is the main phase present. Hardness measurements indicate that Al-Si thin film reached a value of 8.8 ± 0.37 GPa, while that of W-Ti-N/Al-Si multilayer reaches values as high as 17.2 ± 0.25 GPa. Tribological tests conducted on the multilayer system revealed interesting results, namely the very low values of the friction coefficient reaching μ ≈ 0.084±0.018 and that of the wear rate showing a value of k <8.7 ± 0.1·10-13 m3/N·m. Results from the present study are promising and provide an good alternative approach toward the reduction of important energy losses related to friction of the iron alloys piston skirts
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    Surface, structural and optical properties dependence of Fe-doped TiO 2 films deposited onto soda–lime–glass
    (Elsevier, 2020) Benyakhlef, M.; Bensouici, F.; Bououdina, M.; Dakhel, A.A.; Tala-Ighil, Razika; Toubanea, M.
    In this study, pure and Fe doped TiO2 thin films have been prepared via sol-gel method using the tetraethyl-orthotitanate as source of Ti and Fe(III) nitrate as a source of Fe3+ doping. XRD patterns exhibit typical peaks of TiO2 anatase phase. SEM observations confirm the nanometer grain size (below 10 nm) without a defined shape. Optical measurements indicate a transparency in the range 80–100%, it increases with Fe doping level while the energy band gap slightly decreases; 3.36 – 3.28 eV. Wettability test shows a super-hydrophilicity of Fe3+ doped TiO2 thin films and the low contact angle is founded for 0.6%Fe. However, no enhancement in photocatalytic activity of Fe doped TiO2 thin films have been achieved. This may be attributed to sodium diffusion from the substrate. The as-prepared nanostructured Fe-doped TiO2 thin films can be used as potential candidate for self-cleaning due to the super-hydrophilicity character in the visible light
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    Neutron characterization of thin layer SnO2/Glass by neutrons reflectometry
    (2009) Khelladi, M. F.; Izerrouken, M.; Kermadi, Salim; Tala-Ighil, Razika; Sali, S.; Boumaour, Messaoud
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    Effect of acid nature in the starting solution on surface and photocatalytic properties of TiO2 thin films
    (Elsevier, 2014) Bensouici, F.; Souier, Tewfik; Iratni, A.; Dakhel, A.A.; Tala-Ighil, Razika; Bououdina, M.
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    Physico-chemical and electrical properties of InSe films
    (Vacuum, 2004) Kobbi, B.; Kesri, N.
    Thin films of InSe were obtained by vacuum evaporation of polycrystalline material onto well cleaned glass substrates. After deposition on a cold substrate the samples were placed in a vacuum-sealed Pyrex tube for the annealing process. Physico-chemical and electrical properties of the InSe layers have been investigated. RBS and X-ray diffraction measurements showed that the InSe phase could be obtained. Electrical properties of the InSe layers are studied for different annealing temperatures. Conductivity measurements show that the behaviour of the films is sensitive to their thermal environment. The conductivity is controlled by grain boundaries. © 2004 Elsevier Ltd. All rights reserved
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    A comparative structural and magnetic study of Fe100-xPdx(x=15, 20 and 36) thin films deposited on Si (100) and glass substrates
    (Elsevier, 2015) Bahamida, Saida; Fnidiki, A.; Laggoun, A.; Guittoum, A.
    Various structural and magnetic characterization techniques have been used to investigate Fe100-xPdx (x=15, 20 and 36) thin films deposited onto silicon and glass substrates, by thermal evaporation technique. X-ray diffraction analysis shows the presence of supersaturated solid solution with bcc structure for Pd concentrations 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. At 20 at% Pd, the magnetic characterization shows a saturation of the bcc (α-FePd) phase and the appearance of the fcc phase. The correlation between the structure and magnetic properties allows us to compare the two substrates effects on deposited thin films. As results, the measurements indicate that the grain size D, the thin film thickness and the d(110) spacing significantly affect the magnetic coercivity HC. The Fe-Pd alloys deposited on a monocrystalline Si (100) and glass substrate show that the coercivity HC is given by the random anisotropy model. & 2015
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    Synthesis, characterization and photocatalytic behavior of Ag doped TiO2 thin film
    (Elsevier, 2015) Bensouici, F.; Souier, T.; Dakhel, A.A.; Iratni, A.; Tala-Ighil, Razika; Bououdina, M.
    In this study, structure, microstructure, optical properties and photocatalytic degradation of Rhodamine B (RhB) have been investigated in an aqueous heterogeneous media containing pure and Ag doped TiO2 nanostructures thin films which were prepared by a simple sol–gel route. Thermal analysis demonstrated that Ag content decreased the temperature of anatase-to-rutile phase transformation. X-ray diffraction analysis confirmed that the prepared nanostructures crystallize within anatase-type structure and that the dopant Ag ions were not fully incorporated within TiO2 host lattice, meanwhile both the refractive index and optical band gap were affected by Ag concentration. The photodegradation of Rhodamine B under UV-C radiation by using pure and Ag-doped TiO2 nanostructures showed that Ag played an important role in a significant improvement of the photodegradation efficiency and that the optimum content of Ag ions was found to be 0.5% molar ratio
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    Aluminium-induced crystallization of amorphous silicon films deposited by DC magnetron sputtering on glasses
    (2011) Kezzoula, F.; Hammouda, A.; Kechouane, M.; Simon, p.; Abaidia, Seddik-El-Hak; Keffous, A.; Cherfi, R.; Menari, H.; Manseri, A.
    Amorphous silicon (a-Si) and hydrogenated amorphous silicon (a-Si:H) films were deposited by DC magnetron sputtering technique with argon and hydrogen plasma mixture on Al deposited by thermal evaporation on glass substrates. The a-Si/Al and a-Si:H/Al thin films were annealed at different temperatures ranging from 250 to 550 °C during 4 h in vacuum-sealed bulb. The effects of annealing temperature on optical, structural and morphological properties of as-grown as well as the vacuum-annealed a-Si/Al and a-Si:H/Al thin films are presented in this contribution. The averaged transmittance of a-Si:H/Al film increases upon increasing the annealing temperature. XRD measurements clearly evidence that crystallization is initiated at 450 °C. The number and intensity of diffraction peaks appearing in the diffraction patterns are more important in a-Si:H/Al than that in a-Si/Al layers. Results show that a-Si:H films deposited on Al/glass crystallize above 450 °C and present better crystallization than the a-Si layers. The presence of hydrogen induces an improvement of structural properties of poly-Si prepared by aluminium-induced crystallization (AIC)