▎ 摘　　要

We have used the Monte Carlo simulation to study the phase diagrams and the magnetic properties of a single nano-graphene layer with next-nearest neighbors coupling J(2) and four-spin interaction J(4). Interesting behaviors have been found. In particular, the nanographene can present tricritical and triple points for appropriate system parameters. (C) 2017 Elsevier B.V. All rights reserved.