Magnetic properties of a ferrimagnetic mixed (1,3/2)(1,3/2) spin chain with inhomogeneous crystal-field anisotropy

Using molecular-field theory and density-matrix renormalization group calculations we investigated the magnetic properties of a ferrimagnetic mixed (1,3/2)(1,3/2) Ising spin chain with inhomogeneous crystal-field anisotropy. Our analysis introduces a clear physical mechanism for the appearance of the magnetic plateaus in the system and for the quantum phase transitions which are present. We consider two cases of interest: when the crystal field anisotropy D1D1 is present only on the spin-1 ions, and when D3/2D3/2 is present only on the spin-3/2spin-3/2 ions. This latter case turns out to be the more interesting one since a plateau at 15 of the saturation magnetization is formed by means of two physically distinct mechanisms. The magnetic change between these two phases is gradual, varying over the region 1/2