▎ 摘　　要

We investigate magnetic properties of graphene by means of the nonperturbative magnetic-field containing relativistic tight-binding approximation method (nonperturbative MFRTB method) that has recently been developed [Phys. Rev. B 97, 195135 (2018)]. The strong diamagnetism of graphene can be reproduced by the nonperturbative MFRTB method. Namely, the sheet magnetization decreases with the magnetic field up to about 12 (T) with the large magnetic susceptibility. The sheet magnetization upturns at about 12 (T) and then turn down again in the high magnetic-field region [>50 (T)] reflecting the complicated magnetic-field dependence of the energy spectrum of graphene. The small value of the effective g-factor, which is observed experimentally, is partially due to the magnetic field induced by the strong orbital diamagnetism of graphene. In addition, it is pointed out that the elkctive g-factor is also reduced by the tilting of the spin orientation caused by the Rashba effect.