SmFeAsO0.78F0.22中Mn掺杂对超导电性的抑制效应

本文报道了Mn替代Fe对最佳掺杂的Sm-1111体系超导电性的影响.通过电输运及磁性质的测量发现Mn对Fe的替代迅速抑制了超导电性.随着Mn含量的增加,体系的电阻率ρ和磁化率M逐渐增大.对于低掺杂x＜0.25%和未掺杂样品,M接近零,对于≤1%,M从室温到超导转变几乎不变,实验指出Fe2+失去其磁性.我们提出这是由于F...

SUPPRESSION OF SUPERCONDUCTIVITY BY MN DOPING IN SmFeAsO_(0.78)F_(0.22)

In this paper,we reported the influence of Mn substitution to Fe on the superconductivity of optimal doped Sm-1111 system.By electric transport property and magnetism measurement,we found that superconductivity was quickly suppressed by Mn doping.The resistivity ρ and magnetization M all increase with the concentration of Mn ions increasing.For the samples with x< 0.25%,M is close to zero.For the samples with x≤ 1%,M almost keeps unchanged from room temperature to above Tc.These results indicate that the Fe2+ in the system has lost its magnetism.We suggest that this is because the 3d electrons of Fe ions hybridize with the 4p electrons of As and 3d electrons in other Fe sites.The hybridized electrons lead to superconductivity.From the ρ～T curves of low-Tdoped samples under different magnetic field,one can see that the curves are almost linear from 300 K to Tc,and the ρ～T relation under magnetic field is similar to that of Bi 2201 superconductors.The substitution of Mn3+ for Fe2+ does not induce the magnetism of Fe.The magnetization of the system comes from the local moment of Mn ions.The introduction of Mn ions decreases the concentration of the carriers and obstructs the long range Fe-As-Fe pdσ hybridization paths and suppresses the superconductivity.