Magnetostrictive anomalies of rare earth Laves phases with morphotropic phase transition

In the recent years, a number of pseudo-binary $RT_2$ Laves phases with morphotropic phase transitions, i.e., systems of compounds having a morphotropic phase boundary in the phase diagram, have attracted special attention in the process of searching for compounds with high or, on the contrary, almost zero magnetostriction values. In this work, we study the magnetic and magnetostrictive properties of multicomponent systems based on compounds Tb$_{0.2}$Dy$_{0.8-x}$Gd$_{x}$Co$_{2}$ and Tb$_{0.2}$Dy$_{0.8-x}$Gd$_{x}$Co$_{1.9}$Al$_{0.1}$, in which a morphotropic phase transition is observed when dysprosium is replaced by gadolinium. A relationship between the temperature behavior, the sign and magnitude of magnetostrictive deformations, and the type of cubic lattice distortion of the studied Laves phases is revealed. In the region of magnetic phase transitions, the magnetocaloric effect is investigated.