Temperature- and pressure-induced valence transition in [formula omitted

Abstract

The temperature dependence of the electrical resistivity ρ ( T ) of EuCo 2 Ge 2 was measured up to 7 GPa in the temperature range 4 K < T < 300 K . At ambient pressure, the magnetic Eu 2 + moments order antiferromagnetically below T N = 23 K . Upon applying pressure, T N increases monotonously. For pressures higher than 3 GPa, the change of the overall shape of ρ ( T ) suggests a temperature- and pressure-induced continuous valence transition from a high-temperature Eu 2 + state to a low-temperature Eu 3 + state.