Magnetization Plateau of the $S=\frac{1}{2}$ Distorted Diamond Spin Chain with Ferromagnetic Interaction

The magnetization process of the $S=1\mathrm{/}2$ distorted diamond spin chain with ferromagnetic interactions is investigated using the numerical diagonalization of finite-size clusters. The level spectroscopy analysis applied for the model with the spin anisotropy indicates that two different magnetization plateau phases appear at 1/3 of the saturation magnetization. The phase diagrams for some typical interaction parameters are presented. In addition the magnetization curves for several typical parameters are obtained.