Magnetization and ground state spin structures of Ising spin system with four-spin interaction

The magnetization of spin S(= 1 2 and 1) Ising systems with bilinear and four-site four-spin interactions has been investigated by making use of the Monte Carlo simulation. In low-temperature region, the magnetization curves show an anomalous inverse inclination and decrease (increase) with the decrease (increase) of temperature within a certain exchange ratio range. The relation between the value of the magnetization at zero-temperature and the spin structure expected for the ground state is discussed.