Comparative Study of Magnetic Behaviour in Three Classic Molecular Magnets

TL;DR

This study compares the magnetic behaviors of three phenalenyl-based organic radicals, revealing distinct magnetic phases and transitions through experimental measurements and modeling.

Contribution

It provides a comparative analysis of three molecular magnets, including phase transition characterization and application of the Bonner Fisher model.

Findings

Antiferromagnetic system fits Bonner Fisher model.

Diamagnetic to paramagnetic transition is first order.

Distinct magnetic behaviors observed in all three systems.

Abstract

We have studied the magnetic properties of three phenalenyl based organic neutral radicals. The first one is a Heisenberg chain antiferromagnet with one unpaired spin per molecule; second one is a diamagnetic, exhibiting a diamagnetic to paramagnetic phase transition at high temperature; the third one comprises of free neutral radicals and shows paramagnetic behaviour. Temperature dependent magnetic susceptibility measurements and isothermal magnetization measurements (as a function of magnetic field) were performed on all the three systems. In the case of the antiferromagnetic system, temperature dependent susceptibility and magnetization isotherms were fitted to the Bonner Fisher model. In the case of second system the diamagnetic to paramagnetic phase transition is investigated by performing isothermal magnetization measurements in the two different phases. The diamagnetic to paramagnetic phase transition seems to be of first order in nature.