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Using the classical Heisenberg model and Monte Carlo simulation, we present a numerical study of the exchange bias effect in doubly inverted core/shell magnetic nanoparticles with spherical morphology. We mainly focus on the influence of the magnetic anisotropy, interface spin–spin exchange coupling and also shell thickness on the hysteresis behaviours of the system. Our results indicate that there exists a critical shell anisotropy acting in the system. Below this critical anisotropy value, bias field exhibits a steep decrease or increase depending on the considered shell thickness value. Moreover, we show that sign and magnitude of the exchange bias can be adjusted by changing the shell thickness of the nanoparticle, keeping the other system parameters fixed, especially for the strong interface coupling regime. [ABSTRACT FROM AUTHOR]

In this work we will theoretically study the ground-state electronic structure of three-electron polygonal quantum dots by means of the configuration interaction method. Transition from a weakly correlated regime to a strongly correlated regime is investigated for quantum dots with hexagonal, square, and triangular geometries. Our numerical results reveal that the ground-state spin and the charge density distribution of the system are sensitive to the shape of the quantum dot. [ABSTRACT FROM AUTHOR]