Simulation On The Microscopic State Change In Magnetizing Process For The Low Dimensional Spin Frustrated Systems

In recent years, many magnetic materials with special properties in the low temperature have been found. When interactions between magnetic atoms in a lattice are incompatible with the spin geometrical arrangement, which precludes the systems get the simultaneous minimization of all interactions, an exotic phenomenon known as geometrical frustration can emerge. The systems cannot get a stable ground state because of geometrical frustration, thus inducing complex and fascinating physical properties in low temperature, such as the special mutistep magnetization behaviors in spin chain system Ca3Co2O6. Although the multiple magnetization plateau behaviors have been found in many materials, the microscopic nature of the system is still not clear.To exploit the three dimensional Ising antiferromagnets on stacked triangular lattices models in frustration systems, we employ Monte Carlo method. To investigate multiple magnetization plateau phenomena and the microscopic mechanisms in the geometrical frustration systems at low temperature, we take advantage of the spin energy distribution and spin stability in the magnetic field. We successfully achieve correspondence between the plateau transitions and the microscopic mechanisms and get the microscopic essence of macroscopic behavior. This paper mainly studies the following aspects:We study the magnetization behaviors in the two mololayers systems with ferromagnetic interlayer nearest neighbor exchange coupling. We find there are three magnetization plateaus and two hysteresis loops. The same width of magnetic hysteresis loops is proportional to the interlayer nearest neighbor exchange coupling constant. By drawing spin configurations, we can find the down spin around by six up spins because of ferromagnetic intralayer nearest neighbor coupling with decreasing magnetic field, the antiferromagnetic intralayer between spins becomes stronger, the number of the up spins is equal to the down spins, thus a magnetization pleateau with zero appears. By taking advantage of the spin energy distribution, we can find the number of the up spin with the highest exchange energy is three times of the absolute values of fraction changes of down spins. The altitude differences between neighboring plateaus are double of the absolute values of fraction changes of down spins. Specially, we study the situation that the interlayer exchange coupling constant is equal to the interlayer nearest neighbor exchange coupling constant, and find that here are three open hysteresis loops and remanent magnetization close to the experimental measurements, and the magnetization plateau value is not simple integer ratio.We study the magnetization behaviors in the two mololayers systems with antiferromagnetic interlayer nearest neighbor exchange coupling. We can find that there are three magnetization plateaus and no hysteresis loops. The value of the magnetic field where magnetization plateau changed is proportional to the interlayer nearest neighbor exchange coupling constant. By drawing spin configurations during the decreasing of the external field, we can find the mismatch of the spin configurations between the two layers, and find the down spin around by six up spins as same as that in the ferromagnetic interlayer coupling. As the magnetic field decreases, the number of the up spins is equal to the down spins, no net magnetization appears. By taking advantage of the spin energy distribution, we find the number of the up spin with the highest exchange energy is two times of the absolute values of fraction changes of down spins, and the altitude differences between neighboring plateaus is double of the absolute values of fraction changes of down spins. Specially, when the interlayer exchange coupling constant is equal to the interlayer nearest neighbor exchange coupling constant, two closed hysteresis loops apear, and the magnetization plateau value is not simple integer ratio.Besides, the result of magnetization behaviors and microscopic spin configuration in many mololayer system with ferromagnetic interlayer coupling is the similar as that in bilayer system with ferromagnetic interlayer coupling.