Magnetic Properties of Spin-1 One-Dimensional Ising System

In this work, we investigated the temperature and applied field dependence of the magnetization and quadrupolar moment of the spin-1 one-dimensional Ising system (S1-1DIS) by using Kaneyoshi approach throughout the Effective Field Theory (EFT). We determined that the S1-1DIS has a first or second order phase transition according to the crystal field, the magnetization of the S1-1DIS has a second-order phase transition for D=0 whereas the quadrupolar moment has no phase transition at Tc. The magnetization of the S1-1DIS has a first-order phase transition for D=-2.6 at Tf but the quadrupolar moment has phase transition at Tf and it increases at T>Tf, paramagnetic magnetic susceptibility decreases monotonically at T>Tc whereas it has a broad maximum at T>Tf. Because of the MT=0.0 at T>Tc and Tf, it can be concluded that susceptibility behaviors in the paramagnetic region result from the quadrupolar moment. On the other hand, the slope of the hysteresis curves of the MT decreases as the temperature increases and they become zero at high temperature. The theoretical first-order phase transition result of the S1-1DIS is the confirmation of the result of KH2PO4 (KPD) firstly reported by Kittel that one-dimensional system of the KPD undergoes a first-order phase transition at T≠0