Department of Physics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
J Phys Condens Matter. 2010 Apr 14;22(14):145701. doi: 10.1088/0953-8984/22/14/145701. Epub 2010 Mar 19.
The results of x-ray diffraction, electrical resistivity, magnetic susceptibility, and (57)Fe and (155)Gd Mössbauer spectroscopy studies of polycrystalline samples of nonsuperconducting GdFeAsO and superconducting Gd(0.84)Th(0.16)FeAsO are reported. The superconductor Gd(0.84)Th(0.16)FeAsO has the onset transition temperature of 54.4(1) K. We find that Fe and Gd magnetic moments in GdFeAsO order antiferromagnetically at 132.7(1) K and 4.1(1) K, respectively. In Gd(0.84)Th(0.16)FeAsO, Fe atoms carry no magnetic moment down to 1.9 K whereas Gd magnetic moments order below 2.9(1) K. This is taken as evidence for the coexistence of Gd magnetic order and superconductivity. The Debye temperatures of GdFeAsO and Gd(0.84)Th(0.16)FeAsO are, respectively, 409(4) and 389(3) K.
报道了多晶非超导 GdFeAsO 和超导 Gd(0.84)Th(0.16)FeAsO 样品的 X 射线衍射、电阻率、磁化率和 (57)Fe 和 (155)Gd Mössbauer 光谱研究结果。超导体 Gd(0.84)Th(0.16)FeAsO 的起始转变温度为 54.4(1) K。我们发现 GdFeAsO 中 Fe 和 Gd 磁矩分别在 132.7(1) K 和 4.1(1) K 处反铁磁有序。在 Gd(0.84)Th(0.16)FeAsO 中，Fe 原子在 1.9 K 以下没有磁矩，而 Gd 磁矩在 2.9(1) K 以下有序。这被认为是 Gd 磁有序和超导性共存的证据。GdFeAsO 和 Gd(0.84)Th(0.16)FeAsO 的德拜温度分别为 409(4) K 和 389(3) K。
