▎ 摘　　要

The magnetic properties of diamond shaped graphene quantum dots have been investigated by varying their sizes with the Monte Carlo simulation. The magnetizations and magnetic susceptibilities have been studied with dilutions x (magnetic atom), several sizes L (carbon atom) and exchange interaction] between the magnetic atoms. The all magnetic susceptibilities have been situated at the transitions temperatures of each parameters. The obtained values increase when increases the values of x, L and J. The effect of exchanges interactions and crystal field on the magnetization has been discussed. The magnetic hysteresis cycles for several dilutions x, sizes L, exchange interactions] and temperatures T. The magnetic coercive increases with increasing the exchange interactions and decreases when the temperatures values increasing. (C) 2018 Elsevier B.V. All rights reserved.