In this work, we use Monte Carlo simulations to study the magnetic properties of a nanowire system based on a honeycomb lattice, in the absence as well as in the presence of both an external magnetic field and crystal...In this work, we use Monte Carlo simulations to study the magnetic properties of a nanowire system based on a honeycomb lattice, in the absence as well as in the presence of both an external magnetic field and crystal field. The system is formed with NL layers having spins that can take the values σ= ± 1/2 and S =±1,0. The blocking temperature is deduced, for each spin configuration, depending on the crystal field A. The effect of the exchange interaction coupling Jp between the spin configurations σ and S is studied for different values of temperature at fixed crystal field. The established ground-state phase diagram, in the plane （Jp, △）, shows that the only stable configurations are： （1/2,0）, （1/2, ＋1）, and （1/2,- 1）. The thermal magnetization and susceptibility are investigated for the two spin configurations, in the absence as well as in the presence of a crystal field. Finally, we establish the hysteresis cycle for different temperature values, showing that there is almost no remaining magnetization in the absence of the external magnetic field, and that the studied system exhibits a super-paramagnetic behavior.展开更多
The exchange interactions of the nearest-neighbor exchange constant between tetrahedral and octahedral sublattices （JAB（x））, nearest-neighbor exchange constant inside tetrahedral sublattice （JAA（x）） and neares...The exchange interactions of the nearest-neighbor exchange constant between tetrahedral and octahedral sublattices （JAB（x））, nearest-neighbor exchange constant inside tetrahedral sublattice （JAA（x）） and nearest-neighbor exchange constant inside octahedral sublattice （JBB（x）） in cobalt and zinc chromites are calculated using the probability distribution. The Curie–Weiss temperature and the critical temperature are deduced using the mean field and the high temperature series expansion theories in ZnxCo1？xCr2O4. The critical exponent associated with the magnetic susceptibility （γ） is deduced for CoCr2O4.展开更多
The effect of Zn doping on the magnetic properties of CdCr2S4 systems is studied by mean field theory and high-temperature series expansion （HTSE）. The nearest neighbouring and the next-neighbouring super-exchange i...The effect of Zn doping on the magnetic properties of CdCr2S4 systems is studied by mean field theory and high-temperature series expansion （HTSE）. The nearest neighbouring and the next-neighbouring super-exchange interactions Jl（x） and J2（x） are evaluated for the spinel system Zn, Cd1-xCr2S4 in the range 0 〈 x 〈 1. The intra-planar and the inter-planar interactions are deduced. The HTSE combined with the Padd approximant method （PA） is applied to the spinel system ZnxCdl-,Cr2S4. The magnetic phase diagram, i.e. Tc versus dilution x, is obtained. The critical exponents associated with the magnetic susceptibility 7 and the correlation length u are deduced. The obtained theoretical results are in agreement with the experimental data obtained by magnetic measurements.展开更多
文摘In this work, we use Monte Carlo simulations to study the magnetic properties of a nanowire system based on a honeycomb lattice, in the absence as well as in the presence of both an external magnetic field and crystal field. The system is formed with NL layers having spins that can take the values σ= ± 1/2 and S =±1,0. The blocking temperature is deduced, for each spin configuration, depending on the crystal field A. The effect of the exchange interaction coupling Jp between the spin configurations σ and S is studied for different values of temperature at fixed crystal field. The established ground-state phase diagram, in the plane （Jp, △）, shows that the only stable configurations are： （1/2,0）, （1/2, ＋1）, and （1/2,- 1）. The thermal magnetization and susceptibility are investigated for the two spin configurations, in the absence as well as in the presence of a crystal field. Finally, we establish the hysteresis cycle for different temperature values, showing that there is almost no remaining magnetization in the absence of the external magnetic field, and that the studied system exhibits a super-paramagnetic behavior.
文摘The exchange interactions of the nearest-neighbor exchange constant between tetrahedral and octahedral sublattices （JAB（x））, nearest-neighbor exchange constant inside tetrahedral sublattice （JAA（x）） and nearest-neighbor exchange constant inside octahedral sublattice （JBB（x）） in cobalt and zinc chromites are calculated using the probability distribution. The Curie–Weiss temperature and the critical temperature are deduced using the mean field and the high temperature series expansion theories in ZnxCo1？xCr2O4. The critical exponent associated with the magnetic susceptibility （γ） is deduced for CoCr2O4.
文摘The effect of Zn doping on the magnetic properties of CdCr2S4 systems is studied by mean field theory and high-temperature series expansion （HTSE）. The nearest neighbouring and the next-neighbouring super-exchange interactions Jl（x） and J2（x） are evaluated for the spinel system Zn, Cd1-xCr2S4 in the range 0 〈 x 〈 1. The intra-planar and the inter-planar interactions are deduced. The HTSE combined with the Padd approximant method （PA） is applied to the spinel system ZnxCdl-,Cr2S4. The magnetic phase diagram, i.e. Tc versus dilution x, is obtained. The critical exponents associated with the magnetic susceptibility 7 and the correlation length u are deduced. The obtained theoretical results are in agreement with the experimental data obtained by magnetic measurements.
