Abstract. The magnetic properties and phase diagrams of a hexagonal nanotube with core-shell structure have been examined within the framework of the mean field theory based on the Bogoliubov inequality as well as the Monte Carlo simulation via the Metropolis algorithm. We have studied in detail the influences of the different exchange couplings and the crystal field on the phase diagrams of the system. This study allowed us to discover the existence of interesting critical phenomena, in particular the compensation behavior. Moreover, we have investigated the behavior of the magnetizations corresponding to each of the phase diagrams in order to verify the obtained results.

Key words: Hexagonal nanotube, Core-shell structure, Mixed spins, Compensation, Phase diagram.