Extended phase diagram in LaFe1-xNixAsO
LaFe1-xNixAsO samples in the whole range of x have been synthesized and characterized via X-ray diffraction, electrical and magnetic measurements. With increasing Ni content, the SDW ordering is drastically suppressed and then superconductivity emerges in a narrow range of 0:03 6 x 6 0:06. The normal state exhibits a resistivity minimum below a characteristic temperature. Such a semiconductor-like behavior can be seen in a wide range of 0:3 6 x 6 0:9, where no superconductivity is observed. At the other end ð0:9 6 x 6 1Þ, the Fe substitution for Ni suppresses the superconductivity in LaNiAsO.