Effects of Indirect Exchange Interactions in a Mixed-Spin Bilayer Film with Nonmagnetic Layers

The magnetic properties (phase diagrams and magnetizations) of a mixed-spin Ising ferrimagnetic bilayer film on the graphene honeycomb lattice where two (A and B) layers separated by a number of nonmagnetic layers are investigated by the use of the effective field theory with correlations. The systems are consisted of two (spin-1/2 and spin-1) magnetic atoms where spin-1 atoms have a single-ion anisotropy. The effects of an indirect exchange interaction between the A and B layers are examined. Some characteristic behaviors have been found in the system, when the single-ion anisotropy takes a large negative value. Some characteristic phenomena of ferrimagnetism, have been found in the thermal variation of magnetization.