Contrasting Pressure Effects in Sr₂VFeAsO₃ and Sr₂ScFePO₃

Abstract

We report the resistivity measurements under pressure of two Fe-based superconductors with a thick perovskite oxide layer, Sr₂VFeAsO₃ and Sr₂ScFePO₃. The superconducting transition temperature T_c of Sr₂VFeAsO₃ markedly increases with increasing pressure. Its onset value, which was T_c^onset=36.4 K at ambient pressure, increases to T_c^onset=46.0 K at ∼4 GPa, ensuring the potential of the “21113” system as a high-T_c material. However, the superconductivity of Sr₂ScFePO₃ is strongly suppressed under pressure. The T_c^onset of ∼16 K decreases to ∼5 K at ∼4 GPa, and the zero-resistance state is almost lost. We discuss the factor that induces this contrasting pressure effect.