DSpace Communauté:http://dspace.univ-tlemcen.dz/handle/112/162020-07-14T10:14:55Z2020-07-14T10:14:55ZModélisation et simulation des propriétés magnétothermique appliqué aux matériaux ferromagnétiques de type Heusler quaternaire.BOUTERFAS, Abirhttp://dspace.univ-tlemcen.dz/handle/112/154602020-03-04T08:37:19Z2019-06-27T00:00:00ZTitre: Modélisation et simulation des propriétés magnétothermique appliqué aux matériaux ferromagnétiques de type Heusler quaternaire.
Auteur(s): BOUTERFAS, Abir
Résumé: Cold production is an essential process for many of the applications developed by man. This need now represents a very important part of the world's electricity consumption. For this reason, a great deal of work is currently being carried out in the field of magnetic refrigeration in order to advance scientific knowledge on magnetic materials. This thesis allowed us to better understand the structural, magnetic, electronic and thermodynamic properties of a class of alloy called the RhRuNdIn quaternary earth-based Heusler alloy. Hence We first used the method of augmented and linearized plane waves (FP-LAPW) implemented in the Wien2k code. Then in the second step we studied the mean field approximation in the framework of the spin Ising model (s=3/2) where we developed a fortran and python program to determine thermodynamic quantities and also we wrote the behaviour of the magneto-caloric effect.2019-06-27T00:00:00ZETUDE DES PROPRIETES DES ALLIAGES HEUSLER A BASE DE Mn EN UTILISANT LES TECHNIQUES DE DATAMINING.KERDOUCI, ASMAhttp://dspace.univ-tlemcen.dz/handle/112/154542020-03-01T09:58:49Z2019-06-30T00:00:00ZTitre: ETUDE DES PROPRIETES DES ALLIAGES HEUSLER A BASE DE Mn EN UTILISANT LES TECHNIQUES DE DATAMINING.
Auteur(s): KERDOUCI, ASMA
Résumé: A significant number of intermetallic Heusler alloys are theoretically predicted to be halfmetals
at room temperature. The prime feature of these alloys is their possible applications in
spintronic. In fact, the relatively high Curie temperatures are desirable in this field so that the
spin polarization can reach 100% at the Fermi level. These alloys are classified into two
categories: the half-Heusler and full-Heusler alloys. A promising class among these materials
is the ferrimagnetic Heusler Mn-Based alloys which received a considerable attention in the
theoretical studies.
In this work, two methods are used: the first one is the ab initio pseudo-potential approach and
the second one is the datamining method to examine the magnetic, structural, mecanical and
electronic properties of Mn Based Heusler alloys.2019-06-30T00:00:00ZModélisation et simulation de l’effet magnétocalorique dans les matériaux Full Heusler inverse à base de terre rare.BOUHEDDADJ, Aminahttp://dspace.univ-tlemcen.dz/handle/112/154502020-03-01T08:38:03Z2019-06-27T00:00:00ZTitre: Modélisation et simulation de l’effet magnétocalorique dans les matériaux Full Heusler inverse à base de terre rare.
Auteur(s): BOUHEDDADJ, Amina
Résumé: Over the past 20 years, research on the magneto-caloric response of materials has grown considerably, mainly
due to the possibility of applying this effect to magnetic refrigeration close to ambient temperature.
This study is devoted to the main families of materials suitable for this application and the procedures proposed
to predict their response. The magnetic, structural, electronic and thermodynamic properties of inverse Heusler
alloys were studied using first principle calculations and mean field theory. To achieve this objective, we first
used the Ab initio method to determine the state densities of the compound and the magnetic properties from
which it was found that the magnetic results of the Rh2PrIn compound are of the ferromagnetic type, with a
magnetic moment about 2.0867 μB for the element Pr .On the other hand, we established the thermodynamic
properties and the magnetocaloric effect of the compound in question by the mean field simulation method
within the framework of the Ising spin model S=1/2 where a program was developed in Fortran and Python,
Therefore, we have obtained a number of results such as the determination of magnetization, critical temperature
and behaviour of magnetization isotherms to a magnetic field applied for our alloy. The approximation of the
mean field presents a second-order transition and also shows the presence of the ferromagnetic order in the
fundamental state, which is in good agreement with the calculations of the first principle2019-06-27T00:00:00ZEtude de l'efficacité de conversion des cellules solaires organiques à base de polymères conjugués P3HT : PCBMBENSENOUCI, Sarrahttp://dspace.univ-tlemcen.dz/handle/112/154112020-02-20T08:03:44Z2019-06-26T00:00:00ZTitre: Etude de l'efficacité de conversion des cellules solaires organiques à base de polymères conjugués P3HT : PCBM
Auteur(s): BENSENOUCI, Sarra
Résumé: The most promising organic photovoltaic cells are based on the combination of fullerenes and electron donor polymers in interpenetrating networks. The interface between the p-type semiconductor and the n-type semiconductor is distributed throughout the volume of the active layer, which makes it possible to obtain a good efficiency of separation of the charges from photo excitons. Generated, very little mobile in organic materials. We describe the different structures of organic photovoltaic cells. We are interested in the GPVDM modeling software to observe the electrical and optical properties of organic cells (P3HT / PCBM, Perovskite).2019-06-26T00:00:00Z