Superconductivity in Ir-doped LaFe1−xIrxAsO

Abstract

We report the realization of superconductivity by 5d element Ir doping in LaFeAsO, a prototype parent compound of high-temperature iron-based superconductors. X-ray diffraction patterns indicate that the material has formed the ZrCuSiAs-type structure with a space group P4/nmm. The systematic evolution of the lattice constants demonstrated that the Fe ions were successfully replaced by Ir. Both electrical resistance and magnetization measurements show superconductivity up to 11.8 K in LaFe1−xIrxAsO. The superconducting transitions at different magnetic fields were also measured yielding a slope of −dHc2/dT=6.7 T/K near Tc. Using the Werthamer-Helfand-Hohenberg formula Hc2=−0.69 (dHc2/dT)∣TcTc, the upper critical field at zero K is found to be about 54 T. Hall-effect measurements indicate that the conduction in this material is dominated by electronlike charge carriers; the charge-carrier density determined at 100 K is about 3.71×1020/cm3, which is close to the LaFeAsO1−xFx system. This is the example of bulk superconductivity induced by replacing the Fe sites with higher d-orbital electrons in FeAs-1111 family, which should add more ingredients to the underlying physics of the iron-based superconductors.

Source-reported materials — not catalogue approval

Similar papers