Ion-exchange synthesis and superconductivity at 8.6 K of $\mathrm{N}{\mathrm{a}}_{2}\mathrm{C}{\mathrm{r}}_{3}\mathrm{A}{\mathrm{s}}_{3}$ with quasi-one-dimensional crystal structure

We report superconductivity in an iron-based layered oxy-pnictide LaOFeP. LaOFeP is composed of an alternate stack of lanthanum oxide (La3+O2-) and iron pnictide (Fe2+P3-) layers. Magnetic and electrical resistivity measurements verify the occurrence of the superconducting transition at approximately 4 K.