The transport properties of Pr_(1.2)Sr_(1.8)Mn_(2)O_(7) and Pr_(1)Sr_(2)Mn_(2)O_(7) under pressure

摘要

This paper reports the electronic transport measurements of the single crystal Pr_(1.2)Sr_(1.8)Mn_(2)O_(7) and Pr_(1)Sr_(2)Mn_(2)O_(7) under pressure. The measurements in the ab plane for Pr_(1.2)Sr_(1.8)Mn_(2)O_(7) show that the pressure induces a phase transition from a semiconducting state to a metallic state at 0.5 GPa, and then the transition temperature decreases rapidly with increasing pressure, indicating the pressure favors the paramagnetic semiconducting state and suppresses the ferromagnetic metallic state after the occurring of the transition. Moreover, for Pr_(1)Sr_(2)Mn_(2)O_(7), the semiconducting-metallic state transition occurs at ambient pressure and the pressure favors the paramagnetic semiconducting state and suppresses the antiferromagnetic metallic state.