By using Monte Carlo simulations, we investigated a triangle double-layer graphene nanoisland with mixed-spin (3/2, 2) configuration. We focused on the effects of crystal-fields, exchange couplings, longitudinal magnetic fields, and temperature on the magnetic properties of the system. Various curves of magnetization, susceptibility, and internal energy as a function of temperature were obtained. We plotted the phase diagrams of blocking temperature in the different parameter planes. We found that increasing |J_ab/J_Z|,J_bb/J_Z, and h/J_Z or weakening |D_b/J_Z| is beneficial to improving the T_B/J_Z, but the T_B/J_Z is very insensitive to changes in the D_a/J_Z and J_aa/J_Z. In addition, it is worth noting that the system can exhibit abundant multiple-loops hysteresis behaviors for certain physical parameters, such as triple, quadruple, quintuple, septuple hysteresis loops.

中文翻译：

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三角形双层石墨烯纳米岛的磁性：蒙特卡洛研究

通过使用蒙特卡洛模拟，我们研究了具有混合自旋（3/2，2）配置的三角形双层石墨烯纳米岛。我们专注于晶体场，交换耦合，纵向磁场和温度对系统磁性能的影响。获得了磁化，磁化率和内能随温度变化的各种曲线。我们在不同的参数平面上绘制了阻塞温度的相图。我们发现，J _ab / J _Z |，J _bb / J _Z和h / J _Z或弱化| D _b / J _Z| 有助于改善T _B / J _Z，但是T _B / J _Z对D _a / J _Z和J _aa / J _Z的变化非常不敏感。此外，值得注意的是，对于某些物理参数，例如三重，四重，五重，七重磁滞回线，系统可以表现出丰富的多循环磁滞行为。