与SrFe 2 As 2相比,其中只有铁具有磁矩,在EuFe 2 As 2中,Eu 2+携带额外的大的局部磁矩。与SrFe_2As_2一样,EuFe_2As_2在高温下也表现出自旋密度波转变,但在20 K附近还表现出Eu ~(2+)量级的磁矩。压力诱导的超导性和Eu 2+秩序的相互作用导致的行为,这是让人想起的再入超导性,因为它是观察到的,例如,在三元Chevrel相或在稀土镍硼碳化物。在这里,我们研究了微妙的相互作用的有序的Eu 2+的时刻和超导电性在EuFe 1.9Co 0.1As 2,其中的应用程序的外部压力使得有可能灵敏地调整的比率的磁性(T_C)和超导(T_{c,onset})临界温度。发现当T_C > T_{c,onset}时,超导电性消失。
英文摘要:
In contrast to SrFe2As2, where only the iron possesses a magnetic moment, in EuFe2As2 an additional large, local magnetic moment is carried by Eu2+. Like SrFe2As2, EuFe2As2 exhibits a spin-density wave transition at high temperatures, but in addition the magnetic moments of the Eu2+ order at around 20 K. The interplay of pressure-induced superconductivity and the Eu2+ order leads to a behavior which is reminiscent of re-entrant superconductivity as it was observed, for example, in the ternary Chevrel phases or in the rare-earth nickel borocarbides. Here, we study the delicate interplay of the ordering of the Eu2+ moments and superconductivity in EuFe1.9Co0.1As2, where application of external pressure makes it possible to sensitively tune the ratio of the magnetic (T_C) and the superconducting (T_{c,onset}) critical temperatures. We find that superconductivity disappears once T_C > T_{c,onset}.
Emergent magnetism, heavy electrons and pressure-induced reentrant superconductivity in the iron substituted 4d transition-metal sulfides
Zhejiang University of Technology(浙江工业大学);Fudan University(复旦大学);Qufu Normal University(曲阜师范大学);Nanjing University of Posts and Telecommunications(南京邮电大学);Suzhou University of Technology(苏州科技大学);Hangzhou Dianzi University(杭州电子科技大学);National Taiwan Normal University(台湾师范大学);Academia Sinica(中央研究院);Zhejiang University(浙江大学);Ningbo University(宁波大学);Hangzhou Normal University(杭州师范大学);Shanghai Jiao Tong University(上海交通大学)
An effective mean field theory for the coexistence of anti-ferromagnetism and superconductivity: Applications to iron-based superconductors and cold Bose-Fermi atomic mixtures
Bulk domain Meissner state in the ferromagnetic superconductor EuFe$_{2}$(As$_{0.8}$P$_{0.2}$)$_{2}$: Consequence of compromise between ferromagnetism and superconductivity
Magnetic competition in iron-based germanide and silicide superconductors
我们解决的铁磁倾向,有害的超导性,相关的氮族元素作为原子与Ge或Si的替代,以及在122和1111铁基超导体的间隔层中的额外的替代。在密度泛函理论中研究了这些取代分别实现的中间化合物。因此,我们挑选出的间隔离子的控制作为一种有效的方式来处理这样的铁磁性,我们还表明,它被抑制在YFe $_2$ Ge $_2$在压力下-然后可以预期,以提高其超导电性。
Magnetism and superconductivity in single crystals $Eu_{1-x}Sr_xFe_{2-y}Co_{y}As_2$
系统地研究了$Eu_{1-x}Sr_xFe_{2-y}$ Co $_{y}As_2$单晶的输运性质。Co掺杂抑制了自旋密度波(SDW)有序化,诱导了超导转变,但由于$Eu^{2+}$自旋的反铁磁有序化导致了电阻率的再进入,表明反铁磁(AFM)与超导之间存在竞争.由于磁场诱导了$Eu^{2+}$自旋从反铁磁性到铁磁性的变磁转变,因此外磁场(H)可以完全抑制电阻率重入。用非磁性Sr $^{2+}$部分取代Eu $^{2+}$,完全破坏$Eu^{2+}$自旋的AFM有序性,显示出无电阻率重入的超导性。这些结果表明,铁基高$T_c$超导体的反铁磁性破坏了超导性,而铁磁性与超导性可以共存。
Topological superconductivity, ferromagnetism, and valley-polarized phases in moire systems: Renormalization group analysis for twisted double bilayer graphene