The magnetic properties of a mixed spin-\((1/2,5/2)\) chain produced in a charge-transfer salt (4-Cl-o-MePy-V)FeCl₄ were investigated. The formation of a mixed spin-\((1/2,5/2)\) chain with a slight bond alternation was confirmed by molecular orbital calculations. An entire magnetization curve was observed until the point of saturation, which included a clear Leib–Mattis (LM) magnetization plateau and subsequent quantum phase transition toward the gapless Luttinger liquid phase. The magnetic susceptibility and specific heat further confirmed the formation of the LM ferrimagnetic state. A \(\sqrt{T} \) contribution was clearly observed in the low-temperature specific heat, which indicated the contributions of the low-energy magnon excitations in the LM ferrimagnetic state. Electron spin resonance analysis was used to evaluate the effective interchain couplings that resulted in the antiferromagnetic order and on-site biaxial anisotropy associated with the spin-flop transition. In addition, the effects of magnetic anisotropy on the low-energy magnon excitations in the LM plateau phase were evaluated.

中文翻译：

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（4-Cl-o-MePy-V）FeCl4中混合自旋[math]链的磁性

混合自旋的磁性\（（（1 / 2,5 / 2）\）研究了电荷转移盐（4-Cl- o -MePy-V）FeCl ₄中产生的链。形成混合自旋\（（（1 / 2,5 / 2）\）通过分子轨道计算证实了具有轻微键交替的链。观察到整个磁化曲线，直到达到饱和点为止，包括清晰的Leib-Mattis（LM）磁化平稳期和随后的量子相向无间隙Luttinger液相的转变。磁化率和比热进一步证实了LM亚铁磁态的形成。一种\（\ sqrt {T} \）在低温比热中清楚地观察到了这种贡献，这表明在LM亚铁磁状态下低能磁振子的贡献。电子自旋共振分析用于评估有效的链间偶联，该偶联导致反铁磁顺序和与自旋跃迁跃迁相关的现场双轴各向异性。此外，还评估了磁各向异性对LM高原相中低能磁振子激发的影响。