▎ 摘　　要

The Monte Carlo simulation has been applied to discuss the step effect on a zigzag graphene nanoribbon structure in a longitudinal magnetic field. The effects of the singe-ion anisotropies, longitudinal magnetic fields and temperature on the magnetization plateaus have been investigated in detail. Our results show that the number of magnetization plateaus for the system dissatisfy 2S + 1 criterion at low temperatures, originating from not only the competition between the anisotropy and the external magnetic field, but also the contributions of edge effects. It has been found that the single-ion anisotropy plays a significant role in modulating the spin configurations of the zigzag graphene nanoribbon structure. In addition, the effects of single-ion anisotropies and external magnetic fields on the magnetization, the susceptibility, the internal energy and the blocking temperature have been examined. (c) 2017 Elsevier Ltd. All rights reserved.