Effects of phosphorous doping on the superconducting properties of SmFeAs(O,F)

• Doping effects of P on the superconducting properties of Sm1111 is studied.
• P doping induces chemical pressure and strongly deteriorate the superconductivity.
• These isovalent doping effects are compared with Mn and Ni doping in FeAs layers.
• Electron type charge carrier dominates in the transport properties.
• Doping without disrupting FeAs layer is a best way for high Tc superconductivity.

The systematic doping effect induced by the isovalent substitution of P for As on the superconducting properties of F-doped SmFeAsO0.88F0.12 (Sm1111) has been studied by physical and magnetic measurements. The cell volume (V) decreases with P doping and the anisotropic chemical pressure might be induced. However, the superconducting transition temperature (Tc) and the upper critical field (Hc2) are suppressed. Thermoelectric power (S) indicates the majority of electron type charge carriers in support of Hall measurements and its magnitude does not change very much for different P concentrations. The present investigation depicts that isovalent substitutions in the FeAs layer strongly deteriorate the superconducting properties of Sm1111 as a result of increase in chemical pressure. These isovalent substitution effects are comparatively discussed with hole (Mn) and electron (Ni) type substitutions in the superconducting layer of Sm1111.