Pressure induced Eu-valence in EuRu2Ge2

The proposed experiment aims to investigate the pressure-evolution of europium valence in EuRu2Ge2 intermetallic compound. EuRu2Ge2 orders ferromagnetically below TC = 62 K. When pressure was applied, the character of the resistivity curve rho(T) shows peaks with character signifying pressure-induced valence transition at about 4-6 GPa. As a hint of valence change, we have performed a compressibility test using in-house experiment of XRD under pressure at room temperature. This measurement showed a sign of compressibility change at about 7-8 GPa. XAS is a unique tool enabling to discriminate the valence state of the magnetic europium atoms. If the valence change will be experimentally confirmed, it will represent first example of pressure-induced valence transition in ferromagnetic Eu-compounds.