Transition to disordered phase and spin dynamics in the two-dimensional ferrimagnetic model

The effect of transition to disordered phase on AC conductivity in the two-dimensional frustrated ferrimagnetic model in the square lattice at T = 0 is investigated. The spin conductivity,sigma(reg)(omega) is determined for different values of frustration parameters J(2S) and J(2S) that separates the different phases such as the ferrimagnetic phase and the collinear phase. We obtain a small influence of this phase transition on spin conductivity. Furthermore, we present the behavior of the half-width of S((q)over-right-arrow,omega) that gives the information about the scattering of magnons at long wavelength range.