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In this work, the full-Heusler GaFeCo 2 is studied using the first-principles method based on density functional theory with the generalized gradient approximation (GGA and GGA+U) and Monte Carlo simulation. The unit cell parameter is optimized, and then the stability of the GaFeCo 2 compound is checked through its negative formation energy E f . The electronic density of states and the electronic band structure show the metallic behavior of GaFeCo 2 . The magnetic moments of the material are investigated, and Fe and Co atoms have the spin states ( S = ± 5 2 ; ± 3 2 ; ± 1 2 ) and ( σ = ± 3 2 ; ± 1 2 ), respectively. In order to perform Monte Carlo simulation, the exchange interactions J Co - Co , J Co - Fe , and J Fe - Fe are estimated based on energy calculations. Thermal magnetization, magnetic susceptibility, and magnetocaloric effects, such as magnetic entropy change and relative cooling power (RCP), are calculated. It is found that GaFeCo 2 is a ferromagnetic material with high Curie temperature T c = 1120 ∘ K and an RCP of about 7.5 J/Kg for a magnetic field of 5T. These results suggest that GaFeCo 2 is a promising candidate for magnetic refrigeration applications. [ABSTRACT FROM AUTHOR]

Using density functional theory calculations within the generalized gradient approximation, the electronic density of states and band structure of NdMnO 3 simple perovskite are analyzed. It is found that the compound behaves as a ferromagnetic half-metal material. By using Monte Carlo simulations within the framework of the Ising model, the effects of the crystal field and the exchange interaction between the magnetic atoms Mn–Mn and Nd–Mn on the magnetization, susceptibility, specific heat, and internal energy are investigated. The magnetocaloric effect of NdMnO 3 is also examined. It is observed that the relative cooling power (RCP) increases when the applied magnetic field or Mn–Mn exchange interaction is increased, whereas the RCP decreases when the crystal field or Nd–Mn exchange interaction is increased. These results show that NdMnO 3 is a potential candidate for use in magnetic refrigeration and spintronic applications. [ABSTRACT FROM AUTHOR]

Based on the density functional theory and the Monte Carlo Simulation (MCS), the structural, the electronic and the magnetic properties of Sr 2 TiMoO 6 double perovskite have been studied with (GGA), (GGA + U) and (GGA + U + SOC) approaches. The lattice parameter, the band structure and the electronic densities of states have been analyzed. Furthermore, the results show a half-metallic behavior of the compound with (GGA + U) . By the energy calculation, Sr 2 TiMoO 6 oxide shows an antiferromagnetic ordering. The exchange coupling of Sr 2 TiMoO 6 has been also computed in order to investigate the magnetic properties by using MCS in the framework of the Ising model. Interesting phenomena have been obtained such as the first-order transitions and multiple hysteresis loops. These results make Sr 2 TiMoO 6 a promising candidate for spintronic applications. [ABSTRACT FROM AUTHOR]

Based on the density functional theory and the Monte Carlo Simulation (MCS), the structural, the electronic and the magnetic properties of Sr 2 TiMoO 6 double perovskite have been studied with (GGA), (GGA + U) and (GGA + U + SOC) approaches. The lattice parameter, the band structure and the electronic densities of states have been analyzed. Furthermore, the results show a half-metallic behavior of the compound with (GGA + U) . By the energy calculation, Sr 2 TiMoO 6 oxide shows an antiferromagnetic ordering. The exchange coupling of Sr 2 TiMoO 6 has been also computed in order to investigate the magnetic properties by using MCS in the framework of the Ising model. Interesting phenomena have been obtained such as the first-order transitions and multiple hysteresis loops. These results make Sr 2 TiMoO 6 a promising candidate for spintronic applications. [ABSTRACT FROM AUTHOR]

In this work, we use integrated semigroups to state results on the existence and uniqueness of integral solutions and solutions for the abstract Cauchy problem x′(t)=Bx(t)+Lxt, t⩾0, where B is a nondensely defined linear operator on a Banach space X. [ABSTRACT FROM AUTHOR]

We have applied Monte Carlo simulation to study the magnetic behavior of a mixed spins S=±5/2,±3/2,±1/2 and σ=±3/2,±1/2 Ising system of a nanographene layer, where the spins S alternate with the spins σ in two interpenetrating sublattices A and B, respectively. The Hamiltonian of the system contains an exchange interaction between nearest neighbors, a longitudinal magnetic field h, and a four-spin interaction J4. The antiferromagnetic and the ferromagnetic exchange interactions have been investigated. Interesting phenomena have been found. In particular, the system can exhibit a compensation temperature in the presence of h and J4. [ABSTRACT FROM AUTHOR]