【摘要】 基于交替自旋链Ising-Hamiltonian模型,采取量子转移矩阵方法,对基于有机分子准一维亚铁磁体热容量在全温区范围内进行了研究.在不同结构序参量比的条件下,热容量曲线呈现双峰结构,显示有机亚铁磁系统在铁磁和反铁磁作用相互竞争下的复杂热力学行为;在逐渐增加外场的情况下,低温区的比热峰向高温区移动,而高温区的比热峰则刚好相反,这意味着其中一峰来源于铁磁相互作用,而另一峰来源于反铁磁相互作用.这与量子Monte Carlo方法和精确对角化方法的结果相比,更符合客观实际,为设计分子磁性材料提供了理论依据.更多还原

【Abstract】 The specific heat C as functions of temperature T and static magnetic field H in an organic molecule-based ferrimagnetism is investigated in terms of an Ising Hamiltonian for an alternating spin chain.The curves of the specific heat show double-peak structure with different parameter ratios,indicating the complex thermodynamic behavior due to the competition of the ferromagnetic interactions and antiferromagnetic interactions.Meanwhile,in the increasing magnetic fields,the sharp peak in low temperature shifts to high temperature and the Schottky-like peak in high temperature shifts to low temperature,indicating the ferromagnetic nature and antiferromagnetic nature,respectively.Compared to those of the Quantum Monte Carlo method and exact diagonalization method,the results of this paper are more precise than them.更多还原