M. BENSEHIL Ilhem

Abstract
This study employs first-principles density functional theory (DFT) calculations within the GGA-PBEsol framework to comprehensively investigate the structural, elastic, electronic, magnetic, and optical properties of CoCrZrAl and RuCrZrGa quaternary Heusler alloys. Both compounds are found to be stable in the ferromagnetic Y-III phase with equilibrium lattice constants of 6.19 Å and 6.24 Å, respectively. Electronic structure calculations reveal a half-metallic character, exhibiting 100 % spin polarization at the Fermi level with minority spin band gaps of 1.18 eV for CoCrZrAl and 1.19 eV for RuCrZrGa. The total magnetic moments are 4 μB and 3 μB, in full agreement with the Slater-Pauling rule. Mechanical property analysis confirms their ductile nature and elastic stability. Furthermore, optical properties, including a high absorption coefficient in the visible and ultraviolet regions, suggest significant potential for optoelectronic applications. These results position CoCrZrAl and RuCrZrGa as promising candidates for advanced spintronic and optoelectronic devices.

Abstract
This study provides a comprehensive investigation into the structural, optoelectronic, and elastic properties of inorganic metal halide perovskites FrBX3 (B = Pb, Zr; X = Br, Cl) using first-principles calculations based on density functional theory (DFT). Structural analysis confirms the stability of these perovskite phases through optimized lattice parameters and positive formation energies. Electronic band structure calculations reveal that FrZnX3 compounds exhibit direct band gaps, while FrPbX3 compounds possess indirect band gaps. Using the GGA-PBE functional, the band gaps are found to decrease in the order: FrPbCl3 (2.237 eV), FrPbBr3 (1.795 eV), FrZnCl3 (1.185 eV), and FrZnBr3 (0.057 eV), highlighting their potential for photovoltaic applications, particularly in solar energy harvesting. The optical properties, evaluated via dielectric functions, absorption coefficients, and refractive indices, demonstrate strong absorption in the visible region, suggesting their suitability as efficient light-absorbing materials. Furthermore, the elastic properties, including elastic constants, bulk modulus, shear modulus, and Poisson’s ratio, confirm the mechanical stability and ductility of all studied compounds, as they satisfy the Born stability criteria. Moreover, the calculated elastic anisotropy indicates that these materials exhibit moderate directional dependence in their mechanical response, which is advantageous for thin-film fabrication processes. Overall, the combination of favorable electronic, optical, and mechanical properties makes these Fr-based perovskites promising candidates for use in next-generation photovoltaic devices and other optoelectronic applications.

Abstract
This study employs first-principles calculations to explore the structural, elastic, electronic, magnetic, and optical properties
of the quaternary Heusler compounds CoFeYSb (Y = V, Ti). The structural analysis confirms that both compounds are most
stable in the YI configuration. CoFeVSb is found to exhibit ferromagnetic behavior, while CoFeTiSb shows ferrimagnetism.
Elastic constants, cohesion energy, and formation energy calculations further validate the stability of the magnetic (I) phase
for both materials. Band structure analysis reveals that these compounds are half-metallic, achieving 100% spin polarization at
the Fermi level, with spin-down energy gaps of 0.55 eV for CoFeVSb and 0.61 eV for CoFeTiSb. The total magnetic moments
comply with the Slater-Pauling 24-electron rule, with values of 3 μB for CoFeVSb and 2 μB for CoFeTiSb. Optical investigations,
including the dielectric function, absorption coefficient, and energy loss function, demonstrate strong absorption in
the visible and ultraviolet ranges. These results highlight the potential of CoFeYSb compounds for advanced optoelectronic
and spintronic applications, offering new opportunities for their integration into electronic and photonic technologies.

This study employs first-principles calculations to explore the structural, elastic, electronic, magnetic, and optical properties of the quaternary Heusler compounds CoFeYSb (Y = V, Ti). The structural analysis confirms that both compounds are most stable in the YI configuration. CoFeVSb is found to exhibit ferromagnetic behavior, while CoFeTiSb shows ferrimagnetism. Elastic constants, cohesion energy, and formation energy calculations further validate the stability of the magnetic (I) phase for both materials. Band structure analysis reveals that these compounds are half-metallic, achieving 100% spin polarization at the Fermi level, with spin-down energy gaps of 0.55 eV for CoFeVSb and 0.61 eV for CoFeTiSb. The total magnetic moments comply with the Slater-Pauling 24-electron rule, with values of 3 μB for CoFeVSb and 2 μB for CoFeTiSb. Optical investigations, including the dielectric function, absorption coefficient, and energy loss function, demonstrate strong absorption in the visible and ultraviolet ranges. These results highlight the potential of CoFeYSb compounds for advanced optoelectronic and spintronic applications, offering new opportunities for their integration into electronic and photonic technologies.

Conforme aux programmes officiels du LMD, ce polycopié de travaux
dirigés de physique II- électricité et magnétisme- s’adresse aux étudiants de première
année universitaire des domaines Science et Technologie (ST), et Sciences de la
Matière (SM). Il est conforme au programme de la 1ère année du socle commun des
deux domaines. Il est conçu de façon à aplanir au mieux les difficultés inhérentes au
discours scientifique tout en conservant la rigueur nécessaire.
Il est enseigné en un semestre, à raison d’une heure et demi de travaux
dirigés. Le programme d’électricité et de magnétisme du S2 se compose de cinq
grands chapitres:
 Rappels mathématiques
 Electrostatique
 Les conducteurs en équilibre électrostatique
 Electrocinétique
 Magnétisme
Dans le premier chapitre, nous présentons à l’étudiant les différents outils
mathématiques dont il aura besoin dans l’étude des différents phénomènes
d’électricité et magnétisme. Nous commençons par une définition des différents
opérateurs ensuite, on rappelle les expressions des éléments de surface et de volume
dans les systèmes de coordonnées cartésiennes, cylindriques et sphériques.
Le deuxième chapitre est consacré à l’étude de l’électrostatique du vide, discipline qui
étudie l’interaction entre elles, de particules immobiles chargées électriquement. Et
4

étudie les forces électriques, les champs électriques et le potentiel électrique dans des
situations électrostatiques.
Les conducteurs sont des milieux dans lesquels existent des charges libres (positives
ou négatives) susceptible de se déplacer sous l'action d'un champ électrique. Cette
caractéristique leur confère des propriétés électrostatiques spécifiques que nous
détaillerons dans le troisième chapitre. Nous décrirons aussi les condensateurs et
introduirons les notions de capacités.
L’électrocinétique est abordée dans la quatrième partie. Cette discipline étudie les lois
qui réagissent la circulation du courant électrique.
Dans le dernier chapitre, on rappelle quelques concepts de base en magnétisme
comme la force magnétique et l’induction magnétique. On rappelle également
quelques lois connues en magnétisme comme la loi de Biot et Savart et la loi de
Faraday.
Chaque chapitre est introduit un résumé et illustré par des exercices qui
constituent une application, à des problèmes concrets, des lois introduites dans le
cours. La résolution de ces exercices permet à l’étudiant de vérifier s’il a bien assimilé
le cours, d’estimer les ordres de grandeur et d’attacher de l’importance à l’analyse
dimensionnelle aux unités de mesures et à la précision d’un résultat numérique.

Thermal evaporation of a 99.99% pure iron powder has been used to deposit a series of iron thin films onto monocrystalline Si (100) substrates. Samples in each series range in thickness from 10 to 70 nm. Before the evaporation, the background pressure was roughly 10-7 mbar; during deposition, the base pressure was less than 2.10-6 mbar. Using the Kα Cu radiation (λ=1.540598 Å) and the 2θ mode of operation, the X-ray diffraction (XRD) technique has been used to study the structural properties. Atomic force microscopy has been used to scan the morphologies of the films. The majority of the films present a flat surface. The static magnetic measurements were performed using a vibrating sample magnetometer (V.S.M.) with the external magnetic field applied parallel and perpendicular to the surface of the films.

All of the films has a (110) texture and was polycrystalline. All of the samples are under tensile stress, as indicated by the positive strain that was observed. It is possible to deduce from the hysteresis loops that for every sample, the easy magnetization axis is found in the film plane. Coercive field values range from 10 to 100 Oe, depending on a number of factors including substrate type, thickness, tension, and particle size. Squareness values up to one have been measured in the longitudinal configuration. All these results will be investigated and presented.

Keywords: Thin films; XRD; Fe; Magnetization; Coercivity.

Abstract—Based on density functional theory, we investigated
the electrical, magnetic, structural, and elastic properties of the
CoFeVSb Heusler compound. The face-centered cubic (FCC)
structure with space group F43m, in which the atoms of Co, Fe,
V, and Sb are positioned at 4d, 4c, 4b, and 4a Wyckoff locations,
respectively, has been estimated to be the most stable structure
energetically.
In the stable state, CoFeVSb is ferromagnetic. The calculated
elastic constants (Cij) demonstrate the mechanical stability and
ductility of CoFeVSb, as well as its interesting elastic anisotropy.
CoFeVSb exhibits important spin polarization and half-metallic
properties, according to electronic calculations. The spin-down
exhibits a semiconductor behavior with an indirect band gap Γ-X
of 0.52 eV due to the Fermi level being situated between the
valence bands 3t 1u and the conduction bands 2e u . These alloys
show promise for spintronic applications since their total
magnetic moment is found to be 3 µB, which satisfies the Slater
Pauling rule.
Keywords— Half-metals; quaternary Heusler alloys; Elastic
properties; Magnetic moment; Electronic properties

Thin films or low-dimensional systems based on ferromagnetic materials are still being intensively studied because
of their relevance both in fundamental physics and in technological applications related to digital data storage and
spintronics, such as read heads and sensors, high density media, magnetic random access memories (MRAM). The
reduced symmetry as well as the strain induced by mismatched substrates may alter deeply the magnetic properties
of such thin films comparative to the bulk, with the possibility to induce new magnetic behaviors [1-3].
Series of Iron thin films have been deposited by thermal evaporation onto Cut substrates from a 99.99% purified
Fe powder. Each series consists of samples with thickness ranging from 10 to 70 nm. The background pressure was
about 10 -7 mbar before evaporation; during deposition the base pressure was lower than 2.10 -6 mbar. The structural
properties have been studied by X-ray diffraction (XRD) technique, working in the mode and with the Kα Cu
radiation (λ=1.540598 Å). The static magnetic measurements were performed by means of a vibrating sample
magnetometer (V.S.M.), with the external magnetic field applied parallel and perpendicular to the surface of the
films. All the films are polycrystalline with a (110) texture. A positive strain was noted indicating that all the samples
are under a tensile stress. The hysteresis loops allow to infer that the easy magnetization axis lies in the film plane for
all the samples. Values of coercive field are between 20 Oe and 130 Oe, influenced by a number of parameters such
as the thickness, stress, grain size, as well as nature of substrate. Values of squareness up to 1 have been measured
in the longitudinal configuration. All these results will be presented and discussed.

Keywords: Thin films, XRD, Fe, Magnetization, Coercivity.

A significant role for solar cells is played in the use of renewable energy. Researchers have been very interested in perovskite solar cells (PSCs) due to its exceptional power conversion efficiency (PCE), low cost, and straightforward production procedure [1-3]. PSCs have recently increased their approved PCE from 3.8% [4] to 25.2% [5], making them attractive options for high-efficiency solar cells.
In this work, the structural, elastic, electronic and optical properties of double perovskites Cs2GeBr6 were studied based on first-principles calculations. The stability of studied compound is ensured by the negative formation enthalpy. The determined elastic constants (Cij) show that Cs2GeBr6 is mechanically stable and ductile, and exhibit a notable elastic anisotropy. Electronic calculations show that the compound has direct band gap (Γ- Γ) semiconductor. The bandgap value of Cs2GeBr6 is 1.01 eV in near ultraviolet and visible region which increases their importance for solar cell and other optoelectronic applications. The optical properties of Cs2GeBr6 show that this compound exhibits excellent light absorption, especially in the ultraviolet range. Due to the suitable bandgap and excellent light absorption, the double perovskite Cs2GeBr6 can be effective candidates for lead-free photovoltaic materials.
Key words: Double perovskite material; Band structure; Optical properties; First-principles calculations

Des couches minces de Fe ont été évaporées sous vide par effet Joule, sur des substrats de Si(111). Les épaisseurs sont confinées dans la gamme de 13 à 69 nm. La caractérisation des couches minces obtenues a été faite par la diffraction des rayons X (DRX), la microscopie à force atomique (AFM) et le magnétomètre à échantillon vibrant (VSM). La DRX a montré que les couches minces de Fe sont polycristallines avec une structure cubique centrée et une direction préférentielle suivant (110), la taille des grains étant confinée entre 30 et 39 nm. Le taux de contrainte ɛ est positif pour la pluparts des échantillons. La microscopie AFM a montré que les échantillons ont une rugosité varie entre 0.5 et 5 nm.
Les cycles d’hystérésis montrent un axe facile dans le plan et un axe difficile perpendiculaire au plan des couches, ainsi qu’une isotropie magnétique planaire pour toutes les couches minces de Fe. Les couches montrent une diminution de la coercivité avec l’augmentation de l’épaisseur jusqu’à une épaisseur limite. Le champ de saturation et le champ coercitif varient entre 43 à 400 Oe et de 7 à 92 Oe, respectivement. Une bonne squareness est observée pour la majorité des couches minces.

Mots clés: Fe, couches minces, DRX, VSM, champ coercitif.

Abstract: The study of Heusler alloys has attracted more attention from the scientific community since Groot's discovery of the first half metallic material, NiMnSb, in 1983[1]. These materials have attracted a lot of attention because of their unusual and interesting structural features, magnetic properties, and several traits, such as metallic, insulating, semiconducting, half-metallic, and spin gapless semiconducting[2]. These materials are used for spintronics and magnetoelectronics applications such as spin filters, spininjection, magnetic tunnel junctions, giant magnetoresistance, spin transfer torque, memory devices, spin caloritronics, magnetic sensors, and neuromorphic and stochastic computing [3-5]. Based on the density functional theory, we have studied the electrical, magnetic, structural, and elastic properties of the FeVYSb(Y=Sc, Y) Heuslers compound in this work. The most stable structure has been found to be energetically favorable in face- centered cubic (FCC) structure with space group F43m, in which Fe, V, Y and Sb atoms are located at 4d, 4c, 4b and 4a Wyckoff positions, respectively. In the stable state, FeVScSb is ferromagnetic while FeVYSb is ferrimagnetic. The determined elastic constants (Cij) show that FeVYSb(Y=Sc, Y) is mechanically stable and ductile, and exhibit a notable elastic anisotropy. Electronic calculations indicate that FeVYSb(Y=Sc, Y) are semiconductors with band gap of 0.37 eV and 0.30 eV respectively. The total magnetic moment of these alloys is found to be equal to 3 µB which follows the Slater Pauling rule. The magnetic moment remain equal to 3 µB under strain, which makes it hopeful in spintronic applications.

Since Groot’s discovery of the first half metallic material, NiMnSb, in 1983, the scientific community has become increasingly interested in the study of Heusler alloys. Due to their unusual and interesting structural characteristics, magnetic properties, and many features, including metallic, insulating, semiconducting, half-metallic, and spin gapless semiconducting, these materials have garnered a lot of attention. These materials are used for spintronics and magnetoelectronics applications such as spin filters, spininjection, magnetic tunnel junctions, giant magnetoresistance, spin transfer torque,memory devices, spin caloritronics, magnetic sensors, and neuromorphic and stochastic computing.
In this work, we have studied the structural, elastic, electronic and magnetic properties of CoFeVSb Heusler compound basing on the density functional theory. The most stable structure has been found to be energetically favorable in face- centered cubic (FCC) structure with space group F43m, in which Co, Fe, V, and Sb atoms are located at 4d, 4c, 4b and 4a Wyckoff positions, respectively. In the stable state, CoFeVSb is ferromagnetic. The determined elastic constants (Cij) show that CoFeVSb is mechanically stable and ductile, and exhibit a notable elastic anisotropy. Electronic calculations indicate that CoFeVSb exhibit half-metallic characteristics with high spin polarisation. For the spin-down, the Fermi level is located between the valence bands 3t1u and the conduction bands 2eu, which leads to a semiconductor behavior with an indirect band gap Γ-X of 0.52 eV. The total magnetic moment of these alloys is found to be equal to 3 µB which follows the Slater Pauling rule, which makes it hopeful in spintronic applications.

Keywords: Half-metals, quaternary Heusler alloys, Elastic properties, Magnetic moment, Electronic properties

Since Groot’s discovery of the first half metallic material, NiMnSb, in 1983, the scientific community has become increasingly interested in the study of Heusler alloys[1]. Due to their unusual and interesting structural characteristics, magnetic properties, and many features, including metallic, insulating, semiconducting, half-metallic, and spin gapless semiconducting, these materials have garnered a lot of attention[2]. These materials are used for spintronics and magnetoelectronics applications such as spin filters, spininjection, magnetic tunnel junctions, giant magnetoresistance, spin transfer torque,memory devices, spin caloritronics, magnetic sensors, and neuromorphic and stochastic computing[3-5]
In this work, we have studied the structural, elastic, electronic and magnetic properties of FeVYSb(Y=Sc, Y) Heuslers compound basing on the density functional theory. The most stable structure has been found to be energetically favorable in face- centered cubic (FCC) structure with space group F43m, in which Fe, V, Y and Sb atoms are located at 4d, 4c, 4b and 4a Wyckoff positions, respectively. In the stable state, FeVScSb is ferromagnetic while FeVYSb is ferrimagnetic. The determined elastic constants (Cij) show that FeVYSb(Y=Sc, Y) is mechanically stable and ductile, and exhibit a notable elastic anisotropy. Electronic calculations indicate that FeVYSb(Y=Sc, Y) are semiconductors with band gap of 0.37 eV and 0.30 eV respectively. The total magnetic moment of these alloys is found to be equal to 3 µB which follows the Slater Pauling rule. The effect of uniform strain on electronic and magnetic properties is also studied, and the analysis show that FeVYSb (Y=Sc, Y) maintains its semi-conductivity in wide range of lattice parameter from 5.84 Ǻ to 6.60 Ǻ for FeVScSb, and from 6.11 Ǻ to 6.70 Ǻ for FeVYSb. The FeVYSb (Y= Sc,Y) Heuslers become half metal when the lattice parameter varies from 6.61 Ǻ to 6.72 Ǻ for FeVScSb and from 6.71 Ǻ to 6.81 Ǻ for FeVYSb. The magnetic moment remain equal to 3 µB under strain, which makes it hopeful in spintronic applications.

This study employs density functional theory to investigate the structural, elastic,
electronic, and magnetic properties of FeVScSb and FeVYSb Heusler compounds.
FeVScSb exhibits ferromagnetic properties in its stable state, whereas FeVYSb
displays ferrimagnetic behavior. The obtained elastic constants (Cij) indicate that
FeVScSb and FeVYSb possess mechanical stability and ductility, while also
displaying a significant degree of elastic anisotropy. The aggregate magnetic
moment of said alloys is determined to be equivalent to 3 μB, in accordance with
the Slater–Pauling principle. The investigation of the impact of uniform strain on
electronic and magnetic characteristics is conducted. The findings indicate that
FeVScSb and FeVYSb exhibit semiconductivity within extensive lattice parameter
intervals, ranging from 5.84 to 6.60 Å for FeVScSb and from 6.11 to 6.70 Å for
FeVYSb. The Heusler compounds FeVScSb and FeVYSb exhibit half-metallic
behavior within a range of lattice parameters. Specifically, FeVScSb displays this
behavior when the lattice parameter varies from 6.61 to 6.72 Å, while FeVYSb
exhibits half-metallicity within the range of 6.71–6.81 Å. Under the influence of
strain, the magnetic moment retains a constant value of 3 μB. Therefore, the
potential for spintronics is promising.

Des séries de couches minces de Fe ont été évaporées sous vide par effet Joule, sur des substrats de silicium et de cuivre. Les épaisseurs sont confinées dans la gamme de 01 à 70 nm. La DRX a montré que les couches minces de Fe sont polycristallines avec une structure cubique centrée et une direction préférentielle suivant (110), la taille des grains étant confinée entre 14,6 et 41,8 nm, et le taux de contrainte ɛ est positif pour la pluparts des échantillons. La microscopie AFM a montré que les échantillons ont une rugosité de surface variant entre 0,4 et 5 nm. Les cycles d’hystérésis montrent un axe facile dans le plan et un axe difficile perpendiculaire au plan des couches, ainsi qu’une isotropie magnétique planaire pour toutes les couches minces de Fe. Les couches montrent une diminution de la coercivité avec l’augmentation de l’épaisseur jusqu’à une épaisseur limite. Le champ de saturation et le champ coercitif varient entre 35 à 400 Oe et de 7 à 130 Oe, respectivement. Une bonne squareness est observée pour la majorité des couches minces.
Mots clés: Fe ; couches minces; évaporation ; DRX; VSM; champ coercitif.

Abstract
Series of iron thin films have been deposited under vacuum, by thermal evaporation, onto monocrystalline Si(100) and
Si(111) substrates. The thickness ranges from 13 to 69 nm. The structural properties have been studied by X-ray diffraction
technique, working in the θ–2θ mode and with the Kα Cu radiation (λ=1.54056 Å). The films morphologies have been
scanned using atomic force microscopy. Most of the films present a flat surface. The static magnetic measurements were
performed by means of a vibrating sample magnetometer, with the external magnetic field applied parallel and perpendicu-
lar to the surface of the films. All the films are polycrystalline and present well defined Bragg peaks. Most of the films are
under stress. The easy magnetization axis lies in the film plane for all the samples. Values of squareness up to 1 have been
measured in the longitudinal configuration. In Fe/Si (100), coercivity seems to depend closely on crystallite size. All these
results will be presented and discussed.

Low dimensional systems based on ferromagnetic (FM) materials have been the subject of
intensive study because of their relevance both in fundamental physics and in technological
applications connected with digital data storage and spintronics, such as reading heads and
sensors, high density media, magnetic random access memories. The low coordination number,
the reduced symmetry, the strain induced by mismatched substrates, the presence of interface or
surface states can profoundly alter the electronic and magnetic properties of thin films or surfaces
with respect to the bulk, with the possibility to induce new magnetic behaviors in a controlled
way.
In this work we have studied the structural and magnetic properties of Fe thin films evaporated
onto Si (111) substrates. The film thickness ranges from 10 to 70 nm. The characterization of the
obtained thin film was performed by the X-ray diffraction (XRD), the force atomic microscopy
(AFM), and vibrating sample magnetometer (VSM) techniques. XRD measurements show that the
films are polycrystalline with centered cubic structures and grow with <110> texture. The grain
size values range from 29,3 to 38,6 nm. Atomic force microscopy (AFM) study reveals smooth
surfaces for the most of the films, whereas some films present small roughness, between 0,5 and 5
nm.
Using VSM, the hysteresis curves show that the easy magnetization axis lies in the film plane for
all the simples, with no magnetic anisotropy within the plane. The coercive field values seem to
decrease with increasing thickness, till a critical value where an increase of Hc appears for t > tc.
Hc value ranges from 7 to 92 Oe, influenced by a number of parameters such as the thickness,
stress, as well as grain size. The saturation field ranges from 43 to 400 Oe. The value of squarness
for majority of samples are greater than 0,7. All these results will be presented and discussed.
Keywords: Thin films; XRD; Fe; Magnetization; Coercive field.

In this work we have studied the structural and magnetic properties of Fe thin films evaporated onto Si (100) substrates. The film thickness ranges from 10 to 70 nm. The characterization of the obtained thin film was performed by the X-ray diffraction (XRD), the force atomic microscopy (AFM), and vibrating sample magnetometer (VSM) techniques. XRD measurements show that the films are polycrystalline with centered cubic structures and grow with <110> texture. The grain size values range from 29,3 to 37,5 nm. Atomic force microscopy (AFM) study reveals smooth surfaces for the most of the films, whereas some films present small roughness, between 0,4 and 4 nm.
Using VSM, the hysteresis curves show that the easy magnetization axis lies in the film plane for all the simples, with no magnetic anisotropy within the plane. The coercive field values seem to decrease with increasing thickness, till a critical value where an increase of Hc appears for t > tc. Hc value ranges from 15 to 96 Oe, influenced by a number of parameters such as the thickness, stress, as well as grain size. The saturation field ranges from 35 to 270 Oe. The value of squarness for majority of samples are greater than 0,7. All these results will be presented and discussed.

Keywords: Thin films; XRD; Fe; Magnetization; Coercive field.

series of iron thin films have been deposited
under vacuum, by thermal evaporation, onto polycrystalline
Cu substrates. The film thickness ranges from 13 to 69 nm.
An X-ray diffraction (XRD) technique, working in the θ–2θ
mode with the Kα Cu radiation (λ = 1.54056 A), has been ˚
used to perform the structural properties. The static mag￾netic measurements were carried out using a vibrating sam￾ple magnetometer (VSM), with the external magnetic field
applied parallel and normal to the surface of the films. All
the films are polycrystalline and present well-defined Bragg
peaks. The easy magnetization axis lies in the film plane
for all the samples, and no in-plane magnetic anisotropy
has been detected for all films. High values of squareness
have been measured in the longitudinal configuration. All
the findings will be presented and discussed.

Series of Iron thin films have been deposited under vacuum, by thermal evaporation, onto Cu substrates. The thickness ranges from 13 to 69 nm. The structural properties have been studied by X-ray diffraction (XRD) technique, working in the ??-2?? mode and with the Kα Cu radiation (λ=1.54056 Å). The static magnetic measurements were performed by means of a vibrating sample magnetometer (V.S.M.), with the external magnetic field applied parallel and perpendicular to the surface of the films. All the films are polycrystalline and present well defined Bragg peaks. The easy magnetization axis lies in the film plane for all the samples. Values of squareness up to 1 have been measured in the longitudinal configuration. All these results will be presented and discussed.
Keywords: Thin films; XRD; Fe; Magnetization; Coercivity.

Series of Iron thin films have been deposited by thermal evaporation onto Si (100) and Si(111) substrates from a 99.99% purified Fe powder. Each series consists of samples with thickness ranging from 13 to 69 nm. The background pressure was about 10-7 mbar before evaporation; during deposition the base pressure was lower than 2.10-6 mbar. The structural properties have been studied by X-ray diffraction (XRD) technique, working in the 2θ mode and with the Kα Cu radiation (λ=1.540598 Å). The static magnetic measurements were performed by means of a vibrating sample magnetometer (V.S.M.), with the external magnetic field applied parallel and perpendicular to the surface of the films. All the films are polycrystalline with a (110) texture. A positive strain was noted indicating that all the samples are under a tensile stress. The hysteresis loops allow to infer that the easy magnetization axis lies in the film plane for all the samples. Values of coercive field are between 7 G and 96 G, influenced by a number of parameters such as the thickness, stress, grain size, as well as nature of substrate. Values of squareness up to 1 have been measured (fig.1) in the longitudinal configuration. All these results will be presented and discussed.

INITIATION AUX LOGICIELS D’ANALYSE DES MATERIAUX PAR DIFFRACTION DES RAYONS X ET DES ELECTRONS

Les techniques de fabrications des couches minces ont acquis un grand progrès et permettent
de synthétiser des matériaux avec une grande pureté. Il existe deux grandes familles de
techniques de dépôts des matériaux sous forme de couches minces ou de multicouches :
méthodes physiques telles que l’évaporation ou la pulvérisation (croissance en phase gazeuse
à partir de jets d’atomes ou de molécules du matériau que l’on veut déposer) et les méthodes
chimiques (en phase liquide généralement, une réaction chimique libère les espèces
nécessaires à la croissance) [1-3].
Nos échantillons ont été réalisés par la technique de l'évaporation sous vide par effet Joule.
Dans cette technique, le dépôt est réalisé par condensation de la vapeur du matériau à déposer
sur le substrat à recouvrir. L’évaporateur que nous avons utilisé, disponible au niveau du
laboratoire de couches minces du département de physique de l'université Ferhat Abbas de
Sétif, est constitué d’une enceinte en forme de cloche en verre démontable reliée au groupe de
pompage, une pompe à palettes, et une pompe à diffusion d’huile refroidie par circulation
d’eau dans un serpentin. Un disque portant le porte-substrat relié au système d’alimentation
est mis sur la cloche, formant ainsi un système fermé. On y trouve aussi un cache fixé à
quelques centimètres au-dessus du porte-substrat. Le chauffage se fait par effet Joule. Les
connexions électriques du creuset se font en raccordant leurs extrémités à des serre-fils
massifs en cuivre.
Une poudre de fer de pureté 99.99% at. est mise dans un creuset de tungstène enrobé
d’alumine. Le creuset est traversé par un courant de 200 A, environ. Avec ce dispositif, nous
avons déposées plusieurs séries de couches minces en fonction du temps de dépôt. Les
substrats utilisés sont divers : conducteurs(Cu), semi-conducteurs (Si et GaAs
monocristallins), isolants (Corning Glass). La pression de base était aux alentours de 10-7
mbar. L’étude est réalisée en fonction de la nature du substrat, de l’épaisseur de la couche
magnétique et de l’angle d’incidence du faisceau d’atomes.
Mots-clés : couches minces, fer, diffraction des rayons X, DRX
[1] A. Richardt et I. Richardt, Les évaporations sous vide, Paris 2000
[2] Donald M. Mattox, Handbook of Physical Vapor Deposition (PVD) processing,
Westwood, New Jersey, U.S.A, 1998
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