Bossoni L, Romanó L, Canfield P C, Lascialfari A
Department of Physics, University of Pavia-CNISM, Via Bassi 6, I-27100 Pavia, Italy.
J Phys Condens Matter. 2014 Oct 8;26(40):405703. doi: 10.1088/0953-8984/26/40/405703. Epub 2014 Sep 17.
We measured the static uniform spin susceptibility of Ba(Fe(1-x)Rh(x))(2)As(2) iron-based superconductors, over a broad range of doping (0.041 ⩽ x ⩽ 0.094) and magnetic fields. At small fields (H ⩽ 1 kOe) we observed, above the transition temperature Tc, the occurrence of precursor diamagnetism, which is not ascribable to the Ginzburg-Landau theory. On the contrary, our data agree with a phase fluctuation model, which has been used to interpret a similar phenomenology occurring in the high-Tc cuprate superconductors. Additionally, in the presence of strong fields, the unconventional fluctuating diamagnetism is suppressed, whereas Ginzburg-Landau fluctuations are found, in agreement with literature.
我们测量了Ba(Fe(1 - x)Rh(x))(2)As(2)铁基超导体在广泛的掺杂范围（0.041 ⩽ x ⩽ 0.094）和磁场下的静态均匀自旋磁化率。在小磁场（H ⩽ 1 kOe）下，我们观察到，在转变温度Tc以上，出现了前驱抗磁性，这无法用金兹堡 - 朗道理论来解释。相反，我们的数据与一个相位涨落模型相符，该模型已被用于解释在高温铜酸盐超导体中出现的类似现象。此外，在强磁场存在的情况下，非常规的涨落抗磁性受到抑制，而金兹堡 - 朗道涨落则被发现，这与文献一致。
