【摘要】 基于交替自旋Ising-Ham ilton ian模型,用量子转移矩阵方法,研究了不同外场条件下准一维基于有机分子亚铁磁体磁化率的结构序参量.对磁化率χ的研究表明:双自由基和单自由基的交替有机自旋链的亚铁磁自旋排列等效于有效自旋S=1/2的铁磁相互作用链,双自由基有机高分子对具有单一成分的有机基于分子亚磁体具有绝对优势.量子Monte Carlo方法和精确对角化方法的计算结果两者相符,且与某些实验结果定性相符.更多还原

【Abstract】 The susceptibility χ as functions of temperature T and static magnetic field B in aorganic molecule-based ferromagnetism is investigated in terms of an Ising Hamiltonian for an alternating spin chain with different parameter ratios and under different external magnetic field. The calculated results show that the ferromagnetic spin alignment in the alternating molecular chains of biradicals and monoradicals is equivalent to the ferromagnetic alignment of the effective S=1/2 spins and indicate that the triradicals have the potential to the building blocks of single-component organic molecule-based ferromagnetics. Our results are consistent with those of the Quantum Monte Carlo simulations and the exact diagonalization method and in qualitative agreement with the experimental ones.更多还原