Using continued fractions we examined the density of states and thermodynamic properties of a few periodic nonuniform spin-1/2 XX chains in a transverse field.We considered the transverse spin dynamics in spin-1/2 XX chain with correlated Lorentzian disorder.
We extend the consideration of the spin-21 transverse XY chain with correlated Lorentzian disorder [Phys. Rev. B 55, 14 298 (1997)] for the case of additional Dzyaloshinskii-Moriya interspin interaction. It is shown how the averaged density of states can be calculated exactly. Results are presented for the density of states and the transverse magnetization.