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We attempt to study the mixed-spin Ising on two decorated ferrimagnetic ternary metallic nanoislands possessing hexagonal and square structures, with a mixture of spin numbers 3/2, 1, and 1/2. Via the finite cluster approximation, the critical and compensation characteristics have been explored by implementing the influences of decorating and interface exchange couplings ( J 1 , J 2 ), along with the crystal fields ( D σ , D S ) on the phase diagrams and magnetizations. In the absence of crystal fields, the hexagonal structure exhibits only the second-order transition with one or two compensation points; meanwhile, the square structure undergoes the multiple transitions behavior (two or three transition temperatures) with a first-order transition at low temperatures. The inclusion of the crystal fields demonstrates the elevation of the ferrimagnetic region of order. Interestingly, we have uncovered under only the effect of D S acting on spin-1 sublattice the occurrence of the first-order with reentrance indicating two and three transitions for the hexagonal and square structures, respectively. Finally, under a uniform crystal field ( D σ = D S = D), the first-order keeps existing only for the square nanoisland. [ABSTRACT FROM AUTHOR]

The mixed spin Ising nanowire with random and dilute crystal fields has been explored based on the finite cluster approximation. Much concern has been addressed in treating the effects of the randomness with two distribution types of the crystal field on the phase diagrams. It has been demonstrated that for a low random crystal field D marked by the fluctuation d, all transition lines are of second order and are not particularly sensitive to the fluctuation; whereas, for high values of D, the transition temperature depends on the fluctuation and may display tricritical points. Under the effect of the dilute crystal field, according to the surface shell coupling strength, the tricritical behavior occurs exclusively for higher values of the concentration p where a large majority of spins are influenced by the crystal field. All these behaviors have been confirmed by examination of magnetizations. [ABSTRACT FROM AUTHOR]