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Multiferroic composites with the composition (1 − x) BaTi0.8Sn0.2O3–(x) La0.5Ca0.5MnO3 (x = 0, 0.3, 0.5, 0.7, 0.9 and 1) were prepared by sol–gel techniques. Rietveld refinements of the composites with 0–3 and 3–0 type connectivities exhibit the formation of pure phases and confirm the fraction of the composite samples. It was found that the composites grain size decreases slightly with increasing the La0.5Ca0.5MnO3 content. Magnetic measurements of the composite ceramics exhibit a gradual increase in saturation and remanent magnetization with increasing La0.5Ca0.5MnO3 content. Dielectric data demonstrate that the composite materials show high values of the dielectric constant in comparison with the parent compound BaTi0.8Sn0.2O3 (BTSO). In addition, an attempt is made to measure the magnetoelectric coupling coefficient and to explain the negative permittivity and losses occurring in these materials at a certain frequency and temperature conditions. [ABSTRACT FROM AUTHOR]

Perovskite manganite La0.5Ca0.5−x□xMnO3 (LCMO) nanomaterials were elaborated using the sucrose modified auto combustion method. Rietveld refinements of the X-ray diffraction patterns of the crystalline structure confirm a single-phase orthorhombic state with Pbnm space group (No. 62). The Ca-vacancies were voluntarily created in the LCMO structure in order to study their influence on the magnetic behaviour in the system. The magnetic susceptibility was found to be highly enhanced in the sample with Ca-vacancies. Paramagnetic-to-ferromagnetic phase transition was evidenced in both samples around 254 K. This transition is, characterized by a drastic jump of the susceptibility in the sample with Ca-vacancies. The maximum of entropy change, observed for both compounds at magnetic field of 6 T was 2.30 J kg−1 K−1 and 2.70 J kg−1 K−1 for the parent compound and the lacunar one respectively. The magnetocaloric adiabatic temperature change value calculated by indirect method was 5.6 K and 5.2 K for the non-lacunar and Ca-vacancy compound, respectively. The Ca-lacunar La0.5Ca0.5−x□xMnO3 (x = 0.05) reported in this work demonstrated overall enhancement of the magnetocaloric effect over the LCMO. The technique used to elaborate LCMO materials was beneficial to enhance the magnetocaloric effect and magnetic behaviour. Therefore, we conclude that this less costly environmentally friendly system can be considered as more advantageous candidate for magnetic refrigeration applications then the commonly Gd-based compounds. [ABSTRACT FROM AUTHOR]

Using Monte Carlo simulations, magnetic properties of the ferromagnetic nanoparticles of Ising spin-1 are investigated in the framework of the Ising model. The system is considered to have a Rubik’s cube structure composed of nanocubes having an equivalent exchange coupling, while, between adjacent nanocubes, the exchange coupling is assumed to vary. Both size effects and system parameters’ influence on phase diagrams of the nanosystem are studied. Thus, the magnetic properties of the system such as the critical temperature, the magnetization, and the coercive field are computed. [ABSTRACT FROM AUTHOR]

We aim in this research paper to investigate and determine the magnetic properties of the simple perovskite PbVO by determining all the stable phases and analyzing and discussing the ground phase diagrams as a first step. As the second one, we established the magnetic properties of the studied compound employing a Monte Carlo simulation method within the framework of the Ising model to further the investigation. As a result of the employment of MCS, we succeed to determine the critical temperature, which is deduced by studying the magnetization, the susceptibility, and the specific heat. Then, comparing the previous experimental results with our theoretical obtained results, we found a good agreement between them. Also, the coupling effect on the transition temperature was shown. Finally, we analyzed the critical behaviors. [ABSTRACT FROM AUTHOR]

In this paper, the electronic, structural, and magnetic properties of transition metal (TM) (V, Cr, Mn, Fe, Co, Ni, Cu)-doped CdSe are investigated using first-principles calculations within the density functional theory (DFT) and the local density approximation (LDA) in connection with the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) implemented in the AKAI MACHIKANEAMA code. The 3 d level locations of majority spin of those magnetic ions are studied. The spin-spin interaction at low concentration between magnetic impurities leads to ferromagnetic behavior. While the increase of TM concentration beyond 10 % leads to antiferromagnetic interactions between the magnetic ions, which suppress the ferromagnetism. Magnetic stability and Curie temperature are also calculated for different TM doping. And finally, two TMs are chosen to make a codoping in CdSe semiconductor material. [ABSTRACT FROM AUTHOR]

Glasses belonging to the series yA2O-(1-y)[0.25(WO3)2-0.75P2O5] ( y=0.10-0.60) are elaborated. DTA experiments reveal that the glass-network of the glasses are broken with increasing of modifier content. EPR spectra show the presence of two signals due to W5+ and Mo5+, as impuritie. The intensity of these EPR centres decreases when the concentration of A2O increases. The variation of Tg upon the modifier content is ascribed to structural changes occurring in the matrix of these glasses. [ABSTRACT FROM AUTHOR]