The magnetic properties of the iron-arsenic compounds Fe 2 As, FeAs and FeAs 2 have been studied with the Mossbauer effect of 57 Fe. Fe 2 As has a Neel temperature of 353K and its magnetic moments align perpendicularly to the c -axis. These results are in agreement with the neutron diffraction measurements. The temperature variations of both the quadrupole interaction and the isomer shift suggest the
利用 57 Fe 的穆斯堡尔效应研究了铁砷化合物 Fe 2 As、FeAs 和 FeAs 2 的磁性。Fe 2 As 的尼尔温度为 353K,其磁矩与 c 轴垂直。这些结果与中子衍射测量结果一致。四极相互作用和异构体位移的温度变化表明二阶磁转变在尼尔温度下开始。FaAs 2 显示出与 5 K 下的四极相互作用相关的双峰,导致即使在低温下也没有磁性排序。FeAs 在 5 K 处的宽吸收光谱表明低温下的磁性有序。
Single crystals of LnFeAsO1−xFx (Ln=La, Pr, Nd, Sm, Gd) and Ba1−xRbxFe2As2: Growth, structure and superconducting properties
crystals of LnFeAsO1−xFx (Ln = La, Pr, Nd, Sm, Gd) and Ba1−xRbxFe2As2 is presented. A high-pressure technique has been applied for the growth of LnFeAsO1−xFx crystals, while Ba1−xRbxFe2As2 crystals were grown using a quartz ampoule method. Single crystals were used for electrical transport, structure, magnetic torque and spectroscopic studies. Investigations of the crystal structure confirmed high structural
介绍了我们对LnFeAsO 1− x F x(Ln = La,Pr,Nd,Sm,Gd)和Ba 1− x Rb x Fe 2 As 2单晶的研究综述。高压技术已应用于LnFeAsO 1- x F x晶体的生长,而Ba 1- x Rb x Fe 2 As 2的生长使用石英安瓿法生长晶体。单晶用于电传输,结构,磁转矩和光谱研究。对晶体结构的研究证实了高度的结构完善性,并显示了超导LnFeAsO 1- x F x晶体中(O,F)位置的不完全占据。在LnFeAsO 1- x F x晶体上的电阻率测量结果表明,在高磁场中跃迁明显变宽,而在Ba 1- x Rb x Fe 2 As 2中的电阻跃迁简单地转移到较低的温度。两种化合物的临界电流密度相对高,并且超过2×10 9 A /米2在7 T.在十五K磁性穿透深度的各向异性,在LnFeAsO测定1- X ˚F X由扭矩磁力晶体是温度依赖性和显然大于上临界场的各向异性。Ba
Phase transition in CaFeAsH: bridging 1111 and 122 iron-based superconductors
CaFeAsH bridges a gap between 1111-type and other 11-, 111- and 122-type iron based superconductors.
CaFeAsH填补了1111型和其他11、111和122型铁基超导体之间的差距。
Superconductivity on Hole-Doping Side of (La<sub>0.5–<i>x</i></sub>Na<sub>0.5+<i>x</i></sub>)Fe<sub>2</sub>As<sub>2</sub>
作者:Akira Iyo、Kenji Kawashima、Shigeyuki Ishida、Hiroshi Fujihisa、Yoshito Gotoh、Hiroshi Eisaki、Yoshiyuki Yoshida
DOI:10.1021/jacs.7b10656
日期:2018.1.10
tuning the reaction temperature according to x. The parent compound, (La0.5Na0.5)Fe2As2 (x = 0), is a nonsuperconductor with a resistivity anomaly at 130 K due to structural and antiferromagnetic transitions. We find that the temperature of the resistivity anomaly decreases with increasing x and that bulk superconductivity emerges for 0.15 ≤ x ≤ 0.35. The maximum transitiontemperature is 27.0 K, for x
(La0.5-xNa0.5+x)Fe2As2 ((La,Na)122) 是一个有趣的系统,因为可以将电子 (x < 0) 或空穴 (x > 0) 掺杂到 Fe2As2 层中,只需更改成分值 x。然而,迄今为止仅合成了 x = 0.1 的非块状超导样品(单晶)。在这里,我们通过传统的固态反应,通过根据 x 调整反应温度,成功合成了具有 0 ≤ x ≤ 0.35 的宽空穴掺杂组成范围的多晶样品。母体化合物 (La0.5Na0.5)Fe2As2 (x = 0) 是一种非超导体,由于结构和反铁磁转变,电阻率在 130 K 处异常。我们发现电阻率异常的温度随着 x 的增加而降低,并且在 0.15 ≤ x ≤ 0.35 时出现体超导。对于 x = 0.3,最大转变温度为 27.0 K。构建了空穴掺杂侧的电子相图。然而,不能合成电子掺杂样品(x < 0);因此,(La,Na)122 电子相图的另一半需要分辨率来研究
Microstructure and superconductivity of Ir-doped BaFe2As2 superconductor
作者:X. L. Wang、H. Y. Shi、X. W. Yan、Y. C. Yuan、Z.-Y. Lu、X. Q. Wang、T.-S. Zhao
DOI:10.1063/1.3290983
日期:2010.1.4
measurements. XRD and SEM results showed that almost single phase samples were obtained. Bulk superconductivity with TC∼28 K was observed in the x=0.10 sample. TC∼28 K is the highest superconducting critical temperature among the reported data for electron-doped AFe2As2-type (A=Ca, Sr, and Ba) superconductors. The upper critical field Hc2(0) reaches as high as 65 T for the x=0.10 sample. The underlying
通过 X 射线衍射 (XRD)、扫描电子显微镜 (SEM)、电阻率和磁化测量来研究具有 Ba(Fe1-xIrx)2As2 (x=0.10、0.15 和 0.20) 标称成分的多晶样品。XRD和SEM结果表明获得了几乎单相的样品。在 x=0.10 样品中观察到 TC∼28 K 的体超导性。TC∼28 K 是已报道的掺电子 AFe2As2 型(A=Ca、Sr 和 Ba)超导体数据中最高的超导临界温度。对于 x=0.10 样品,上临界场 Hc2(0) 高达 65 T。结合共掺杂情况讨论了基础物理学。