  The magnetic properties and phase diagrams of the mixed spin-1 and spin-1/2
Ising model on a checkerboard square structure have been studied using the
Monte Carlo simulations based on the Metropolis update protocol. The system
consists of four quartets of alternative spin configuration. The effect of the
exchange interactions J and crystal field D on the magnetic properties,
critical and compensation temperatures, susceptibility, and specific heat of
the system have been investigated. The phase diagrams, T-J and T-D, for
different values of the exchange interactions and crystal field have been
examined. We found that the compensation temperature starts to evolve for J1 <
0.6 of the spin-1 assembly and for J2 > 1.6 for spin-1/2. On the other hand,
the effect of ferrimagnetic coupling does not show any threshold value; in this
case, the compensation temperature is constant. Regarding the crystal field
strength, the threshold value of D > -0.8 has been observed. We obtain the N-,
Q- and P-type compensation behaviors in the system. We have observed that the
phase diagrams exhibit only a second-order phase transition to a paramagnetic
phase; hence, the system does not show the tricritical point. The magnetic
hysteresis cycles of the mixed spin-1 and spin-1/2 on a checkerboard square
structure for different values of the exchange interactions, temperatures, and
crystal fields have been found. Finally, the system exhibits the
superparamagnetism behavior for a fixed value of the temperature and crystal
field.
