Discovery of Magnetic Phase Transitions in Heavy-Fermion Superconductor CeRh2As2

We report on the specific heat studies performed on a new generation of CeRh₂As₂ single crystals. Superior quality of the samples and dedicated experimental protocol allowed us to observe an antiferromagneticlike behavior in the normal state and to detect the first-order phase transition of magnetic origin within the superconducting state of the compound. Although in the available literature the physical behavior of CeRh₂As₂ is most often described with the use of quadrupole density wave scenario, we propose an alternative explanation using analogies to antiferromagnetic heavy-fermion superconductors CeRhIn₅ and Ce₂RhIn₈.