Numerical study of magnetization processes in rare-earth tetraborides

Abstract

We present a simple model for a description of magnetization processes in rare-earth tetraborides. The model is based on the coexistence of two subsystems, and, namely, the spin subsystem described by the Ising model and the electronic subsystem described by the Falicov-Kimball model on the Shastry-Sutherland lattice (SSL). Moreover, both subsystems are coupled by the anisotropic spin-dependent interaction of the Ising type. We have found, that the switching on of the spin-dependent interaction $({J}_{z})$ between the electron and spin subsystems and taking into account the electron hopping on the nearest $(t)$ and next-nearest $({t}^{\ensuremath{'}})$ lattice sites of the SSL leads to a stabilization of magnetization plateaus. In addition, to the Ising magnetization plateau at ${m}^{sp}/{m}_{s}^{sp}=1/3$ we have found three relevant magnetization plateaus located at ${m}^{sp}/{m}_{s}^{sp}=1/2$, 1/5, and 1/7 of the saturated spin magnetization ${m}_{s}^{sp}$. The ground states corresponding to magnetization plateaus have the same spin structure consisting of parallel antiferromagnetic bands separated by ferromagnetic stripes.