The magnetic properties of a diluted spin-2 and spin-5/2 ferrimagnetic Ising system are investigated on the basis of the effective-field theory with correlations. In particular, the effect of a positive single-ion anisotropy D on the compensation temperature in a pure system with D only on spin-5/2 atoms is investigated, in order to clarify the characteristic feature of the temperature dependence of the total magnetization M observed in a molecular-based magnetic material, . The influences of D and the concentrations of magnetic atoms on the properties of the system on a honeycomb lattice are examined. The results show that several (two or three) compensation points are possible in the diluted system with special values of D and concentrations of magnetic atoms.

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Within the framework of the effective‐field theory, the phase diagram (transition temperature Tc and critical transverse field Ωc) of a ferroelectric bilayer system is studied on the basis of the spin‐1/2 transverse Ising model consisting of two different ferroelectric slabs with the same thickness L. The dependences of Tc and Ωc on L and the inter‐slab exchange coupling R are examined and discussed. We find some unexpected phenomena in the phase diagrams of the system with a thin thickness L, such as the frustration effect due to the large values ofRand transverse field Ω.

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Within the framework of the effective-field theory, the phase diagram (transition temperature T c and critical transverse field W c ) of a ferroelectric bilayer system is studied on the basis of the spin-1/2 transverse Ising model consisting of two different ferroelectric slabs with the same thickness L. The dependences of T c and W c on L and the inter-slab exchange coupling R are examined and discussed. We find some unexpected phenomena in the phase diagrams of the system with a thin thickness L, such as the frustration effect due to the large values of R and transverse field W.