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, σreg(ω) is determined for different values of frustration parameters J2S and J2s 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→,ω) that gives the information about the scattering of magnons at long wavelength range.