Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in ${\text{Ca}}_3{\text{Co}}_2{\text{O}}_6$ compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

Figure 1

(Color online) Evaluated DOS $\text{ln}\left[g\left(E,M\right)\right]$ for ${\text{Ca}}_3{\text{Co}}_2{\text{O}}_6$ compound and curves in (b)–(d) represent the cross-sectioned $\text{ln}\left[g\left(E,M\right)\right]$ at various energy values $E$.

Figure 2

(Color online) Simulated $M/M_0$ as a function of $T$ and $B$.

Figure 3

(Color online) Comparison of (a),(c) $M/M_0$ and (b),(d) $U/N$ as a function of $B$ calculated from WL method with computed using the Metropolis algorithm at $T=10\text{K}$ and $T=2\text{K}$.

Figure 4

(Color online) Simulated curves of $M/M_0$ as a function of $B$ (a) for different spans and (b) for various lattice sizes $L$ at $T=2\text{K}$.