Ground-state magnetic properties of the spin-2 transverse Ising model

Abstract

The ground-state magnetic properties of the spin-2 transverse Ising model with a longitudinal crystal field are studied within the framework of mean-field theory (MFT) and effective-field theory (EFT), respectively. The phase diagrams and magnetization curves are examined in detail. It is found that the system exhibits a tricritical behavior in the ground-state phase diagrams. Some interesting phenomena have been found, especially the first-order phase transition from one ordered phase to the other ordered phase, which is due to the high spin. The spin correlation has important effect on the magnetic properties of the system. We also find that the ground-state phase diagrams of the spin-2 transverse Ising model are very different from those of the spin-3/2 transverse Ising model. r

The phase diagrams of a spin-1 transverse Ising model

“…1 of Ref. [16], there are first-order orderedordered phase transitions, because in the S 2 , S z representation, the eigenvalue of The heavy line linked with these tricritical points is the tricritical line.…”

“…1 of Ref. [16], which are the ground-state phase diagrams of the spin-2 transverse Ising model. We see that these two figures are very different.…”

“…(13), |n l S is the numerically obtained eigenvector and l l the eigenvalue of the matrix in Eq. (10), in which E i has been replaced by x [16,17]. The results of the numerical calculation show that F(x) is the odd function of x while Q(x) and G(x) are the even functions.…”

High field magnetization ofFePS3

“…High-field magnetisation experiments of Ising systems, particularly for a transverse field, are of particular interest. The model has been extensively studied theoretically and, despite its simplicity, can result in fascinating behaviour such as quantum phase transitions and tricritical points [15][16][17][18]. Such experiments on FePS 3 would determine whether the compound is a satisfactory physical representation to test the theories.…”

Mixed spin-1 and spin-2 Ising model: study of the ground states

“…Higher spin systems present diverse and interesting physical phenomena, such as the spin-1 Ising system with bilinear and biquadratic interactions that presents magnetic relaxation [35], first-order transition [36], and tricritical behavior in the presence of a transverse crystal field [37], possible reentrant phenomenon due to the competitive effects between exchange interactions in the Hamiltonian [38], dynamic compensation temperature in an oscillating external magnetic field on alternate layers of a hexagonal lattice [39], as well as reentrant and double reentrant phenomena [40] and the existence of tricritical points when the system is under the effect of random crystal field and surface exchange interactions [41]. The spin-2 Ising model have been investigated on a bilayer square lattice [42], and in the presence of a longitudinal crystal field within the framework of mean-field theory and effective-field theory [43], among others. The mixing of higher spins compounds presents even more interesting properties.…”