Observation of thermodynamics originating from a mixed-spin ferromagnetic chain

We present a model compound that forms a mixed-spin ferromagnetic chain. Our material design, based on the organic radicals, affords a verdazyl-based complex (p-Py-V)(2)[Mn(hfac)(2)]. The molecular orbital calculations of the compound indicate the formation of a mixed-spin-(1/2, 1/2, 5/2) ferromagnetic chain. The temperature dependence of magnetic susceptibility reveals its ferromagnetic behavior. The magnetic specific heat exhibits a double-peak structure and indicates a phase transition at the low-temperature peak. The observed characteristics are explained using the quantum Monte Carlo calculations. Furthermore, the modified spin-wave theory verifies that the double-peak structure of the specific heat significantly reflects the relative ration of the acoustic excitation band and the optical excitation gap.

Automated summary

We present a model compound for a mixed-spin ferromagnetic chain, designed based on organic radicals. The compound shows ferromagnetic behavior and exhibits a double-peak structure in its magnetic specific heat, indicating a phase transition. Quantum Monte Carlo calculations and modified spin-wave theory explain the observed characteristics.