rachid masrour - Academia.edu (original) (raw)

Papers by rachid masrour

Superlattices and Microstructures, 2013

New theoretical investigation on the electronic structure and magnetic interaction for both cubic... more New theoretical investigation on the electronic structure and magnetic interaction for both cubic SrFeO 3 and CaFeO 3 oxides: Comparison between GGA and GGA+U approaches, Superlattices and Microstructures (2013),

Plasmonics

The current COVID-19 pandemic has resulted in an urgent need for methods to decontaminate respira... more The current COVID-19 pandemic has resulted in an urgent need for methods to decontaminate respirators masks for reuse while keeping them intact and functional. The severe shortage of professional masks such as N95 and FFP2 has necessitated their reuse over long periods. A very promising method is the pasteurization of these masks by thermoplasmonic heat generated by plasmonics nanoparticles when they are irradiated by light. Under illumination at its plasmonic resonance, a metal nanoparticle features enhanced light absorption, turning it into an ideal nano-source of heat, remotely controllable using light. In this work, we propose a numerical study based on the finite element method (FEM) of the thermoplasmonic properties of silver nanoparticles (AgNPs) decorating polypropylene (PP) fibers which is a basic material for the manufacture of these masks. The surface plasmon resonance (SPR) of these nanostructures was investigated through the computation of the complex effective dielectric permittivity and the absorption cross section in the near UV-visible (NUV-Vis) range. First, the SPR characteristics of AgNPs for different morphologies are determined from the absorption spectra, including the SPR-peak position λ max and the electric field enhancement. Second, we determine the power absorbed by an individual AgNP of different morphologies. From this, we calculate the internal temperature increase of the particle at the plasmonic resonance. The last step is devoted to the determination of the temperature profile in the surrounding medium in order to better understand and design the plasmon-assisted heating processes at the nanometric scale.

Plasmonics

In this paper, the optical and thermoplasmonics properties of nanocomposites consisting of spheri... more In this paper, the optical and thermoplasmonics properties of nanocomposites consisting of spherical gold nanoparticles (AuNPs) integrated in Al 2 O 3 matrix are determined using the Finite Element Method (FEM). Firstly, the refractive index (n) , extinction coefficient () , absorption coefficient (a) , and optical conductivity () are calculated from the effective complex permittivity obtained by solving the Laplace's equation for different size and concentration of nanoparticles. The surface plasmon resonance (SPR) properties of AuNPs are optimized from the peak presented in the absorption coefficient spectrum. The results show that the optical parameters n, , a , and undergo a strong variation around the wavelength max corresponding to the SPR phenomenon. The value of max increases from 560 to 600nm when the radius of the particles varies between r = 5 and r = 30nm. The effect of the AuNP concentration on the band gap energy E g (eV) of Au-Al 2 O 3 nanocomposites is also studied, a shift from Eg = 5.34 to Eg = 5.49eV is observed when the concentration of the AuNPs increases from 0 to 0.82%. The electric field enhancement induced by the AuNPs at plasmonic resonance is also determined depending to the particle size; the results show that the enhancement factor increases from g = 4.71 to g = 6.95 when the radius of the AuNPs increases from r = 5 to 30nm. The thermal dissipation of the plasmonic energy of spherical of our system dispersed in the Al 2 O 3 matrix is determined considering the Joule effect which occurs by the oscillation of the charges at the plasmonic resonance. The generated thermal power by particles is calculated for different sizes, which allows to calculate the thermal power per gram of particles depending on the intensity of the incident electric field. The results show that the plasmonic thermal power is almost identical for small particles when the radius is less than r = 15nm and increases considerably when the size increases from r = 15 to 30nm. For a fixed size and incident field amplitude, we calculated the temperature change in the nanocomposites Au-Al 2 O 3 depending of time for different particle concentrations; the temperature variation curves obtained are linear as a function of time.

Journal of Magnetism and Magnetic Materials, 2015

Self-consistent ab initio calculations Q2 , based on density functional theory (DFT) approach and... more Self-consistent ab initio calculations Q2 , based on density functional theory (DFT) approach and using a full potential linear augmented plane wave (FLAPW) method, are performed to investigate both electronic and magnetic properties of the Fe 3 O 4. Polarized spin and spin-orbit coupling are included in calculations within the framework of the antiferromagnetic state between two adjacent Fe plans. The antiferromagnetic and ferromagnetic energies of Fe 3 O 4 systems are estimated. Magnetic moment considered to lie along (010) axes are computed. Obtained data from ab initio calculations are used as input for the high temperature series expansions (HTSEs) calculations to compute other magnetic parameters.The exchange interactions between the magnetic atoms Fe-Fe in Fe 3 O 4 are given using the mean field theory. The high temperature series expansions (HTSEs) of the magnetic susceptibility of with the magnetic moments, m Fe in Fe 3 O 4 is given up to sixth order series in (1/k B T). The Néel temperature T N is obtained by HTSEs of the magnetic susceptibility series combined with the Padé approximant method. The critical exponent γ associated with the magnetic susceptibility is deduced as well.

Journal of Superconductivity and Novel Magnetism, 2014

ABSTRACT The external magnetic field induced the reorientation of magnetization of a ferromagneti... more ABSTRACT The external magnetic field induced the reorientation of magnetization of a ferromagnetic (or antiferromagnetic) treated within the framework of many-body Green’s function theory by considering all components of the magnetization. We present a new method for the calculation of expectation values in terms of the eigenvalues and eigenvectors of the equations of motion matrix for the set of Green’s functions. Magnetization and magnetic susceptibility are investigated when an external magnetic field is applied in (x-z)-plane. The mean field theory is applied to calculate the nearest neighbour and the next-neighbour super-exchange J 1(Cr−Cr) and J 2(Cr−(Mg(Cu)−O)−Cr), respectively, for the Mg x Cu1−x Cr2O4 in the range of 0 ≤ x ≤ 1. The intra-planar and the inter-planar interactions are deduced. The high-temperature series expansions (HTSEs) are derived for the magnetic susceptibility and two-spin correlation functions for a Heisenberg ferromagnetic model on the B-spinel lattice. The calculations are developed in the framework of the random-phase approximation (RPA). The magnetic-phase diagram is deduced. A spin-glass phase is predicted for intermediate range of concentration. The spin glass is obtained. The obtained results are comparable with those obtained by magnetic measurements. The critical exponents associated with the magnetic susceptibility (γ) and the correlation lengths (ν) have been deduced. The obtained values are comparable to those of 3D Heisenberg model.

The magnetic susceptibility of a semi-infinite ferromagnetic films with a simple cubic lattice an... more The magnetic susceptibility of a semi-infinite ferromagnetic films with a simple cubic lattice and the face centered cubic lattice is investigated by the method of exact high-temperature series expansions (HTSE) extrapolated with the Padé approximants method for Heisenberg, XY and Ising models. The magnetic phase diagrams in ( () ν τ c , x ) plane are obtained. The value of the percolation threshold p x is obtained. The p x is defined at which 0 = c τ .

Journal of Magnetism and Magnetic Materials, 2015

The self-consistent ab initio calculations, based on DFT (Density Functional Theory) approach and... more The self-consistent ab initio calculations, based on DFT (Density Functional Theory) approach and using FLAPW (Full potential Linear Augmented Plane Wave) method, are performed to investigate both electronic and magnetic properties of the Mn 2 Au. Polarized spin and spin-orbit coupling are included in calculations within the framework of the antiferromagnetic state between two adjacent Mn plans. Magnetic moment considered to lie along (110) axes are computed. Obtained data from ab initio calculations are used as input for the high temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The exchange interactions between the magnetic atoms Mn-Mn in Mn 2 Au are given by using the experiment results and the mean field theory. The High Temperature Series Expansions (HTSEs) of the magnetic susceptibility with the magnetic moments in Mn 2 Au (m Mn) is given up to tenth order series in, 1/k B T. The Néel temperature T N is obtained by HTSEs combined with the Padé approximant method. The critical exponent associated with the magnetic susceptibility is deduced as well.

Journal of Magnetism and Magnetic Materials, 2015

The magnetic properties of spins-S and  Ising model on the Bethe lattice have been investigated ... more The magnetic properties of spins-S and  Ising model on the Bethe lattice have been investigated by using the Monte Carlo simulation. The thermal total magnetization and magnetization of spins S and  with the different exchange interactions, different external magnetic field and different temperatures have been studied. The critical temperature and compensation temperature have been deduced. The magnetic hysteresis cycle of Ising ferrimagnetic system on the Bethe lattice has been deduced for different values of exchange interactions between the spins S and , for different values of crystal field and for different sizes. The magnetic coercive filed has been deduced.

International Journal of Modern Physics B, 2011

The crossover of dilution in the critical exponent associated with the thermodynamic properties i... more The crossover of dilution in the critical exponent associated with the thermodynamic properties in the magnetic materials via Monte Carlo simulations is observed. The obtained results of critical exponent associated with the magnetic susceptibility, specific heat and correlation length for the ZnCr 2x Al 2-2x S 4, Cd 1-y Cr 2-2x In y+2x Se 4 and Zn 1-x Mn x Te systems are comparable with those given by the experiment results.

Journal of Superconductivity and Novel Magnetism, 2015

The self-consistent ab initio calculations, based on density functional theory (DFT) approach and... more The self-consistent ab initio calculations, based on density functional theory (DFT) approach and using fullpotential linear augmented plane wave (FLAPW) method, are performed to investigate both electronic and magnetic properties of the MnSb compounds. Polarized spin and spin-orbit coupling are included in calculations within the framework of the ferromagnetic state between two adjacent Mn atoms. The ferromagnetic energy of MnSb systems is obtained. Magnetic moment considered to lie along the (001) axes are computed. The exchange interactions between the magnetic atoms Mn-Mn in MnSb are given using the mean field theory. Obtained data from ab initio calculations are used as input for the high-temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The HTSEs of the magnetic susceptibility of the magnetic moments in MnSb (m Mn) is given up

The European Physical Journal Applied Physics, 2014

Self-consistent ab initio calculations, based on the density functional theory (DFT) approach and... more Self-consistent ab initio calculations, based on the density functional theory (DFT) approach and using the full potential linear augmented plane wave (FLAPW) method, are performed to investigate both the electronic and magnetic properties of CrSb compounds. Spin-polarised calculations, including the spin-orbit interaction, are used to determine the energy of the ferromagnetic (FM) and antiferromagnetic (AFM) states of CrSb. Magnetic moments considered along the (0 0 1) axis are computed. Data obtained from ab initio calculations are used as input for high temperature series expansions (HTSEs) to compute other magnetic parameters. The exchange interactions between the magnetic atoms Cr-Cr in CrSb are studied using the mean field theory. The high temperature series expansions (HTSEs) of the magnetic susceptibility are given up to tenth order (x = J 1(Cr-Cr)/kBT). The Néel temperature TN is obtained by HTSEs of the magnetic susceptibility combined with the Padé approximant method. The critical exponent γ associated with the magnetic susceptibility is deducedas well.

Journal of Materials Science, 2014

The compositional dependence of the magnetic and magnetocaloric properties of La0.6Pr0.1Ba0.3MnO3... more The compositional dependence of the magnetic and magnetocaloric properties of La0.6Pr0.1Ba0.3MnO3 (LPBMO) and La0.6Pr0.1Ba0.3Mn0.9Fe0.1O3 (LPBMFO) were investigated. Polycrystalline samples were prepared by the standard solid-state reaction method. Temperature-dependent magnetization measurements and Arrott analysis reveal second-order ferromagnetic transitions in both samples with Curie temperature increasing with doping iron from 94 K for LPBMO to 277 K for LPBMFO. Magnetic entropy change ∣DeltaStextM∣| {\Delta S_{\text{M}} } |∣DeltaStextM∣|ΔSM| was calculated by applying the thermodynamic Maxwell equation to a series of isothermal field-dependent magnetization curves. However, the analysis of the magnetocaloric effect (MCE) using Landau theory of phase transition shows that the contributions to the free energy from the presence of ferromagnetic clusters are strongly influencing the MCE by coupling with the order parameter around the Curie temperature.

Journal of Superconductivity and Novel Magnetism, 2014

The magnetic properties of ferromagnetic La 0.7 Ca 0.3 3MnO 3 perovskite have been studied using ... more The magnetic properties of ferromagnetic La 0.7 Ca 0.3 3MnO 3 perovskite have been studied using Monte Carlo simulations within the Ising model framework. The considered Hamiltonian includes the first nearest neighbor, an external magnetic field, and a crystal field. The thermal magnetizations and magnetic susceptibilities are computed for a fixed system size N = 5. In addition, the critical temperature is deduced. The magnetization versus the exchange interactions and crystal field are deduced for a fixed system size. The magnetic hysteresis cycle versus temperature is also established.

Journal of Superconductivity and Novel Magnetism, 2014

ABSTRACT The magnetic properties of antiferromagnetic MnTe alloys have been studied by Monte Carl... more ABSTRACT The magnetic properties of antiferromagnetic MnTe alloys have been studied by Monte Carlo simulations within Ising model framework. The considered Hamiltonian includes nearest-neighbor interactions, external magnetic field, and crystal field. Magnetizations and magnetic susceptibility versus temperature are computed for a fixed size. The blocking temperature is established, and the magnetic hysteresis cycle is deduced for different values of temperature. The remanent magnetization and the coercive field are obtained. In addition, the magnetization versus the first exchange interaction (J(1)) with a fixed value of the second exchange interaction (J(2)) and the third second interaction (J(3)) is estimated. The magnetization versus the crystal field is deduced.

Superlattices and Microstructures, 2013

ABSTRACT

Physics Letters A, 2008

The magnetic properties of a ferromagnet spinS a disordered semi-infinite system with a face-cent... more The magnetic properties of a ferromagnet spinS a disordered semi-infinite system with a face-centered cubic lattice are investigated using the high-temperature series expansions technique extrapolated with Padé approximants method for Heisenberg, X Y and Ising models. The reduced critical temperature of the system τ c = kB Tc 2S(S+1) J b is studied as function of the thickness of the film and the exchange interactions in the bulk, and within the surfaces J b , J s and J ⊥ , respectively. It is found that τ c increases with the exchange interactions of surface. The magnetic phase diagrams (τ c versus the dilution x) and the percolation threshold are obtained.

Physica Scripta, 2009

ABSTRACT We recently found that there were misprints in figure 2 of this paper. The corrected ver... more ABSTRACT We recently found that there were misprints in figure 2 of this paper. The corrected version is given in the PDF.

Journal of the Korean Physical Society, 2014

The mean field theory (MFT) and high temperature series expansions (HTSEs) of the magnetic suscep... more The mean field theory (MFT) and high temperature series expansions (HTSEs) of the magnetic susceptibility are used to investigate the magnetic properties in simple cubic (sc) antiferromagnetic with spins S = 1 and S = 3/2 films by using both the Ising and the XY models. The films consisting of l = 2, 3, 4, 5, 6 and infinite (∞) interacting layers are studied up to sixth order series in x = βJ where β = 1 k B T , for free-surface boundary conditions. The effects of finite size on the critical-point behavior are studied by extrapolation of the high-temperature series. The Néel temperature T N (l) as a function of the spin layers numbers l is obtained by using HTSEs of the magnetic susceptibility series, the Padé approximant method and the MFT theory. The critical exponent γ associated with the magnetic susceptibility is deduced. The Néel temperatures TN (l) for the l-layers films are estimated from the divergence of the staggered susceptibility with exponents γ(1) and γ(2) for the Ising and the XY models, respectively. This is consistent with the basic assumptions of scaling laws. The shift exponents of the Néel temperature for the Ising and the XY models, respectively, are estimated.

Journal of Superconductivity and Novel Magnetism, 2011

... R. Masrour Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University... more ... R. Masrour Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, Safi, Morocco M. Hamedoun · A. Benyoussef Institute for Nanomaterials and Nanotechnologies, Rabat, Morocco ... Catal. ...

Superlattices and Microstructures, 2013

New theoretical investigation on the electronic structure and magnetic interaction for both cubic... more New theoretical investigation on the electronic structure and magnetic interaction for both cubic SrFeO 3 and CaFeO 3 oxides: Comparison between GGA and GGA+U approaches, Superlattices and Microstructures (2013),

Plasmonics

The current COVID-19 pandemic has resulted in an urgent need for methods to decontaminate respira... more The current COVID-19 pandemic has resulted in an urgent need for methods to decontaminate respirators masks for reuse while keeping them intact and functional. The severe shortage of professional masks such as N95 and FFP2 has necessitated their reuse over long periods. A very promising method is the pasteurization of these masks by thermoplasmonic heat generated by plasmonics nanoparticles when they are irradiated by light. Under illumination at its plasmonic resonance, a metal nanoparticle features enhanced light absorption, turning it into an ideal nano-source of heat, remotely controllable using light. In this work, we propose a numerical study based on the finite element method (FEM) of the thermoplasmonic properties of silver nanoparticles (AgNPs) decorating polypropylene (PP) fibers which is a basic material for the manufacture of these masks. The surface plasmon resonance (SPR) of these nanostructures was investigated through the computation of the complex effective dielectric permittivity and the absorption cross section in the near UV-visible (NUV-Vis) range. First, the SPR characteristics of AgNPs for different morphologies are determined from the absorption spectra, including the SPR-peak position λ max and the electric field enhancement. Second, we determine the power absorbed by an individual AgNP of different morphologies. From this, we calculate the internal temperature increase of the particle at the plasmonic resonance. The last step is devoted to the determination of the temperature profile in the surrounding medium in order to better understand and design the plasmon-assisted heating processes at the nanometric scale.

Plasmonics

In this paper, the optical and thermoplasmonics properties of nanocomposites consisting of spheri... more In this paper, the optical and thermoplasmonics properties of nanocomposites consisting of spherical gold nanoparticles (AuNPs) integrated in Al 2 O 3 matrix are determined using the Finite Element Method (FEM). Firstly, the refractive index (n) , extinction coefficient () , absorption coefficient (a) , and optical conductivity () are calculated from the effective complex permittivity obtained by solving the Laplace's equation for different size and concentration of nanoparticles. The surface plasmon resonance (SPR) properties of AuNPs are optimized from the peak presented in the absorption coefficient spectrum. The results show that the optical parameters n, , a , and undergo a strong variation around the wavelength max corresponding to the SPR phenomenon. The value of max increases from 560 to 600nm when the radius of the particles varies between r = 5 and r = 30nm. The effect of the AuNP concentration on the band gap energy E g (eV) of Au-Al 2 O 3 nanocomposites is also studied, a shift from Eg = 5.34 to Eg = 5.49eV is observed when the concentration of the AuNPs increases from 0 to 0.82%. The electric field enhancement induced by the AuNPs at plasmonic resonance is also determined depending to the particle size; the results show that the enhancement factor increases from g = 4.71 to g = 6.95 when the radius of the AuNPs increases from r = 5 to 30nm. The thermal dissipation of the plasmonic energy of spherical of our system dispersed in the Al 2 O 3 matrix is determined considering the Joule effect which occurs by the oscillation of the charges at the plasmonic resonance. The generated thermal power by particles is calculated for different sizes, which allows to calculate the thermal power per gram of particles depending on the intensity of the incident electric field. The results show that the plasmonic thermal power is almost identical for small particles when the radius is less than r = 15nm and increases considerably when the size increases from r = 15 to 30nm. For a fixed size and incident field amplitude, we calculated the temperature change in the nanocomposites Au-Al 2 O 3 depending of time for different particle concentrations; the temperature variation curves obtained are linear as a function of time.

Journal of Magnetism and Magnetic Materials, 2015

Self-consistent ab initio calculations Q2 , based on density functional theory (DFT) approach and... more Self-consistent ab initio calculations Q2 , based on density functional theory (DFT) approach and using a full potential linear augmented plane wave (FLAPW) method, are performed to investigate both electronic and magnetic properties of the Fe 3 O 4. Polarized spin and spin-orbit coupling are included in calculations within the framework of the antiferromagnetic state between two adjacent Fe plans. The antiferromagnetic and ferromagnetic energies of Fe 3 O 4 systems are estimated. Magnetic moment considered to lie along (010) axes are computed. Obtained data from ab initio calculations are used as input for the high temperature series expansions (HTSEs) calculations to compute other magnetic parameters.The exchange interactions between the magnetic atoms Fe-Fe in Fe 3 O 4 are given using the mean field theory. The high temperature series expansions (HTSEs) of the magnetic susceptibility of with the magnetic moments, m Fe in Fe 3 O 4 is given up to sixth order series in (1/k B T). The Néel temperature T N is obtained by HTSEs of the magnetic susceptibility series combined with the Padé approximant method. The critical exponent γ associated with the magnetic susceptibility is deduced as well.

Journal of Superconductivity and Novel Magnetism, 2014

ABSTRACT The external magnetic field induced the reorientation of magnetization of a ferromagneti... more ABSTRACT The external magnetic field induced the reorientation of magnetization of a ferromagnetic (or antiferromagnetic) treated within the framework of many-body Green’s function theory by considering all components of the magnetization. We present a new method for the calculation of expectation values in terms of the eigenvalues and eigenvectors of the equations of motion matrix for the set of Green’s functions. Magnetization and magnetic susceptibility are investigated when an external magnetic field is applied in (x-z)-plane. The mean field theory is applied to calculate the nearest neighbour and the next-neighbour super-exchange J 1(Cr−Cr) and J 2(Cr−(Mg(Cu)−O)−Cr), respectively, for the Mg x Cu1−x Cr2O4 in the range of 0 ≤ x ≤ 1. The intra-planar and the inter-planar interactions are deduced. The high-temperature series expansions (HTSEs) are derived for the magnetic susceptibility and two-spin correlation functions for a Heisenberg ferromagnetic model on the B-spinel lattice. The calculations are developed in the framework of the random-phase approximation (RPA). The magnetic-phase diagram is deduced. A spin-glass phase is predicted for intermediate range of concentration. The spin glass is obtained. The obtained results are comparable with those obtained by magnetic measurements. The critical exponents associated with the magnetic susceptibility (γ) and the correlation lengths (ν) have been deduced. The obtained values are comparable to those of 3D Heisenberg model.

The magnetic susceptibility of a semi-infinite ferromagnetic films with a simple cubic lattice an... more The magnetic susceptibility of a semi-infinite ferromagnetic films with a simple cubic lattice and the face centered cubic lattice is investigated by the method of exact high-temperature series expansions (HTSE) extrapolated with the Padé approximants method for Heisenberg, XY and Ising models. The magnetic phase diagrams in ( () ν τ c , x ) plane are obtained. The value of the percolation threshold p x is obtained. The p x is defined at which 0 = c τ .

Journal of Magnetism and Magnetic Materials, 2015

The self-consistent ab initio calculations, based on DFT (Density Functional Theory) approach and... more The self-consistent ab initio calculations, based on DFT (Density Functional Theory) approach and using FLAPW (Full potential Linear Augmented Plane Wave) method, are performed to investigate both electronic and magnetic properties of the Mn 2 Au. Polarized spin and spin-orbit coupling are included in calculations within the framework of the antiferromagnetic state between two adjacent Mn plans. Magnetic moment considered to lie along (110) axes are computed. Obtained data from ab initio calculations are used as input for the high temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The exchange interactions between the magnetic atoms Mn-Mn in Mn 2 Au are given by using the experiment results and the mean field theory. The High Temperature Series Expansions (HTSEs) of the magnetic susceptibility with the magnetic moments in Mn 2 Au (m Mn) is given up to tenth order series in, 1/k B T. The Néel temperature T N is obtained by HTSEs combined with the Padé approximant method. The critical exponent associated with the magnetic susceptibility is deduced as well.

Journal of Magnetism and Magnetic Materials, 2015

The magnetic properties of spins-S and  Ising model on the Bethe lattice have been investigated ... more The magnetic properties of spins-S and  Ising model on the Bethe lattice have been investigated by using the Monte Carlo simulation. The thermal total magnetization and magnetization of spins S and  with the different exchange interactions, different external magnetic field and different temperatures have been studied. The critical temperature and compensation temperature have been deduced. The magnetic hysteresis cycle of Ising ferrimagnetic system on the Bethe lattice has been deduced for different values of exchange interactions between the spins S and , for different values of crystal field and for different sizes. The magnetic coercive filed has been deduced.

International Journal of Modern Physics B, 2011

The crossover of dilution in the critical exponent associated with the thermodynamic properties i... more The crossover of dilution in the critical exponent associated with the thermodynamic properties in the magnetic materials via Monte Carlo simulations is observed. The obtained results of critical exponent associated with the magnetic susceptibility, specific heat and correlation length for the ZnCr 2x Al 2-2x S 4, Cd 1-y Cr 2-2x In y+2x Se 4 and Zn 1-x Mn x Te systems are comparable with those given by the experiment results.

Journal of Superconductivity and Novel Magnetism, 2015

The self-consistent ab initio calculations, based on density functional theory (DFT) approach and... more The self-consistent ab initio calculations, based on density functional theory (DFT) approach and using fullpotential linear augmented plane wave (FLAPW) method, are performed to investigate both electronic and magnetic properties of the MnSb compounds. Polarized spin and spin-orbit coupling are included in calculations within the framework of the ferromagnetic state between two adjacent Mn atoms. The ferromagnetic energy of MnSb systems is obtained. Magnetic moment considered to lie along the (001) axes are computed. The exchange interactions between the magnetic atoms Mn-Mn in MnSb are given using the mean field theory. Obtained data from ab initio calculations are used as input for the high-temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The HTSEs of the magnetic susceptibility of the magnetic moments in MnSb (m Mn) is given up

The European Physical Journal Applied Physics, 2014

Self-consistent ab initio calculations, based on the density functional theory (DFT) approach and... more Self-consistent ab initio calculations, based on the density functional theory (DFT) approach and using the full potential linear augmented plane wave (FLAPW) method, are performed to investigate both the electronic and magnetic properties of CrSb compounds. Spin-polarised calculations, including the spin-orbit interaction, are used to determine the energy of the ferromagnetic (FM) and antiferromagnetic (AFM) states of CrSb. Magnetic moments considered along the (0 0 1) axis are computed. Data obtained from ab initio calculations are used as input for high temperature series expansions (HTSEs) to compute other magnetic parameters. The exchange interactions between the magnetic atoms Cr-Cr in CrSb are studied using the mean field theory. The high temperature series expansions (HTSEs) of the magnetic susceptibility are given up to tenth order (x = J 1(Cr-Cr)/kBT). The Néel temperature TN is obtained by HTSEs of the magnetic susceptibility combined with the Padé approximant method. The critical exponent γ associated with the magnetic susceptibility is deducedas well.

Journal of Materials Science, 2014

The compositional dependence of the magnetic and magnetocaloric properties of La0.6Pr0.1Ba0.3MnO3... more The compositional dependence of the magnetic and magnetocaloric properties of La0.6Pr0.1Ba0.3MnO3 (LPBMO) and La0.6Pr0.1Ba0.3Mn0.9Fe0.1O3 (LPBMFO) were investigated. Polycrystalline samples were prepared by the standard solid-state reaction method. Temperature-dependent magnetization measurements and Arrott analysis reveal second-order ferromagnetic transitions in both samples with Curie temperature increasing with doping iron from 94 K for LPBMO to 277 K for LPBMFO. Magnetic entropy change ∣DeltaStextM∣| {\Delta S_{\text{M}} } |∣DeltaStextM∣|ΔSM| was calculated by applying the thermodynamic Maxwell equation to a series of isothermal field-dependent magnetization curves. However, the analysis of the magnetocaloric effect (MCE) using Landau theory of phase transition shows that the contributions to the free energy from the presence of ferromagnetic clusters are strongly influencing the MCE by coupling with the order parameter around the Curie temperature.

Journal of Superconductivity and Novel Magnetism, 2014

The magnetic properties of ferromagnetic La 0.7 Ca 0.3 3MnO 3 perovskite have been studied using ... more The magnetic properties of ferromagnetic La 0.7 Ca 0.3 3MnO 3 perovskite have been studied using Monte Carlo simulations within the Ising model framework. The considered Hamiltonian includes the first nearest neighbor, an external magnetic field, and a crystal field. The thermal magnetizations and magnetic susceptibilities are computed for a fixed system size N = 5. In addition, the critical temperature is deduced. The magnetization versus the exchange interactions and crystal field are deduced for a fixed system size. The magnetic hysteresis cycle versus temperature is also established.

Journal of Superconductivity and Novel Magnetism, 2014

ABSTRACT The magnetic properties of antiferromagnetic MnTe alloys have been studied by Monte Carl... more ABSTRACT The magnetic properties of antiferromagnetic MnTe alloys have been studied by Monte Carlo simulations within Ising model framework. The considered Hamiltonian includes nearest-neighbor interactions, external magnetic field, and crystal field. Magnetizations and magnetic susceptibility versus temperature are computed for a fixed size. The blocking temperature is established, and the magnetic hysteresis cycle is deduced for different values of temperature. The remanent magnetization and the coercive field are obtained. In addition, the magnetization versus the first exchange interaction (J(1)) with a fixed value of the second exchange interaction (J(2)) and the third second interaction (J(3)) is estimated. The magnetization versus the crystal field is deduced.

Superlattices and Microstructures, 2013

ABSTRACT

Physics Letters A, 2008

The magnetic properties of a ferromagnet spinS a disordered semi-infinite system with a face-cent... more The magnetic properties of a ferromagnet spinS a disordered semi-infinite system with a face-centered cubic lattice are investigated using the high-temperature series expansions technique extrapolated with Padé approximants method for Heisenberg, X Y and Ising models. The reduced critical temperature of the system τ c = kB Tc 2S(S+1) J b is studied as function of the thickness of the film and the exchange interactions in the bulk, and within the surfaces J b , J s and J ⊥ , respectively. It is found that τ c increases with the exchange interactions of surface. The magnetic phase diagrams (τ c versus the dilution x) and the percolation threshold are obtained.

Physica Scripta, 2009

ABSTRACT We recently found that there were misprints in figure 2 of this paper. The corrected ver... more ABSTRACT We recently found that there were misprints in figure 2 of this paper. The corrected version is given in the PDF.

Journal of the Korean Physical Society, 2014

The mean field theory (MFT) and high temperature series expansions (HTSEs) of the magnetic suscep... more The mean field theory (MFT) and high temperature series expansions (HTSEs) of the magnetic susceptibility are used to investigate the magnetic properties in simple cubic (sc) antiferromagnetic with spins S = 1 and S = 3/2 films by using both the Ising and the XY models. The films consisting of l = 2, 3, 4, 5, 6 and infinite (∞) interacting layers are studied up to sixth order series in x = βJ where β = 1 k B T , for free-surface boundary conditions. The effects of finite size on the critical-point behavior are studied by extrapolation of the high-temperature series. The Néel temperature T N (l) as a function of the spin layers numbers l is obtained by using HTSEs of the magnetic susceptibility series, the Padé approximant method and the MFT theory. The critical exponent γ associated with the magnetic susceptibility is deduced. The Néel temperatures TN (l) for the l-layers films are estimated from the divergence of the staggered susceptibility with exponents γ(1) and γ(2) for the Ising and the XY models, respectively. This is consistent with the basic assumptions of scaling laws. The shift exponents of the Néel temperature for the Ising and the XY models, respectively, are estimated.

Journal of Superconductivity and Novel Magnetism, 2011

... R. Masrour Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University... more ... R. Masrour Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, Safi, Morocco M. Hamedoun · A. Benyoussef Institute for Nanomaterials and Nanotechnologies, Rabat, Morocco ... Catal. ...