Investigating 4f ferrroquadrupolar phase transitions: local moment realizations of nematicity

Electronic nematicity, in which the electronic degrees of freedom break the rotational symmetry of the lattice, has been exhibited by many materials including various high-temperature superconductors. A local realization of electronic nematicity is also seen in 4f intermetallic materials undergoing ferroquadrupolar order. In these materials the lattice of local 4f electronic multiplets collectively and spontaneously break the rotational symmetry of the point group of the lattice. Here we measure the quadrupole-strain (nematic) susceptibility of TmAg₂, which exhibits a ferroquadrupolar phase transition at 5.0K. We implement an elastoresistivity technique previously used in probing another 4f intermetallic, YbRu₂Ge₂ , and extend this technique to investigate the nematic behavior of TmAg₂ while applying a “transverse” magnetic field to suppress the ferroquadrupolar phase transition to 0K.