Monte Carlo investigation of mixed spin Ising 2D-nanoparticles

The magnetic properties of mixed spin-1/2 and spin-1 Ising 2D-nanoparticles (circle and square) with core-shell structure are examined by the use of the Monte Carlo simulation. The phase diagrams are investigated and show qualitatively interesting features. In particular, three and four physically different phases are identified for the square and circle nanoparticles, respectively. These phases are separated by different transitions that could be called ordinary, core and shell transitions according to the strengths of the exchange interactions.