科研之友
微信
新浪微博
Facebook
分享链接
摘要
Superconductivity with a T-c of about 10 K is observed in the Ni-doped SmFe1-xNixAsO system. The measurements of resistivity and magnetic susceptibility show that the spin-density wave (SDW) order is quickly suppressed with increasing Ni content, and superconductivity emerges as x >= 0.04. T-c(mid) shows a maximum of 10.8 K at x = 0.06, and it drops to lower than 2 K as x > 0.12. Meanwhile, the upper critical field (H-c2(0)) is estimated to be about 40 T for the optimally-doped sample (x = 0.06). The normal state thermopower is negative for all the Ni-doped samples, indicating that an electron-type charge carrier dominates in the transport properties. Moreover, the magnitude of the room-temperature thermopower increases with increasing Ni content, and then shows a broad peak around x = 0.06. We found that there is an obvious correlation between the anomalously enhanced thermopower and superconductivity. A phase diagram is derived based on the transport measurements and a dome-like T-c(x) curve is established.
