Phase Transitions and Magnetic Properties of Zigzag Triangular Nanographenes: Monte Carlo Simulation

The magnetic phase transition and magnetic properties in zigzag triangular nanographenes (ZTN) with mixed spins 2 and 5/2 are studied by Monte Carlo simulation. The ground state phase diagrams of ZTN are obtained under effect crystal fields, magnetic field, and exchange interactions. The thermal magnetizations and magnetic susceptibilities of ZTN are obtained for a fixed magnetic parameter. The variation of Néel temperature is deduced by varying the edge atoms on a side of the zigzag triangular nanographenes. The variation of total magnetizations with the crystal field is shown. The total magnetic hysteresis cycles with mixed spins S = 2 and σ = 5/2, for several size of the nanographenes, exchange interactions and temperatures are found.