Аннотация:
Cascade of phase transitions in GdFe$_3$(BO$_3$)$_4$ at 156 K, 37 K and 9 K has been detected by specific heat measurements and further studied by Raman scattering and Nd$^{3+}$ spectroscopic probe method. A weakly first-order structural phase transition at 156 K is followed by a second-order antiferromagnetic ordering phase transition at 37 K and a first-order spin-reorientational phase transition at 9 K.