Manipulating superconducting phases via current-driven magnetic states in rare-earth-doped CaFe2As2

Abstract

Inhomogeneous superconductivity in rare-earth (RE)-doped CaFe 2 As 2 (Ca122) compounds leads to a novel state of matter in which the superconducting and magnetic states can be simultaneously controlled by using an electric current (I). Both La-and Ce-doped Ca122 single crystals show a very broad superconducting transition width (ΔT c) due to their non-bulk nature. Surprisingly, ΔT c becomes sharper or broader after an electric current larger than a threshold value (I t) is applied, with a concomitant change in the normal-state magnetism. The sharpened (broadened) ΔT c is accompanied by a decrease (an increase) in the amplitude of the ferromagnetic signals. The sensitive changes in the superconductivity and magnetism that occur when an external current is applied are related to the inhomogeneous electronic states that originate from the Fe magnetic state and/or self-organized superconducting/magnetic composites in Ca122 compounds. These discoveries shed new light on the role of Fe in Fe-based superconductors and will provide new ideas for the design of novel superconducting devices.

Hydrothermal Synthesis and Crystal Structure of a (Ba0.54K0.46)4Bi4O12 Double-Perovskite Superconductor with Onset of the Transition Tc ∼ 30 K

“…59 (OH) 0.41 . 28 This kind of irregular ZFC curve was also observed for rare-earth-doped CaFe 2 As 2 and Ca intercalates of MoS 2 superconductors, 29,30 probably because of the mixed superconducting and nonsuperconducting phases. Samples synthesized at 180, 200, and 220 °C also displayed shielding volume fractions of approximately 9%, 46%, and 60% at 5 K with onsets of the transition T c mag of approximately 8, 26.5, and 28 K, respectively (Figure S3).…”

Role of Lanthanide in the Electronic Properties of RbLn 2Fe4As4O2 (Ln = Sm and Ho) Superconductors

“…Different rare-earth elements affect not only the magnetic structure of iron, but also the absolute value of the magnetic moment of iron, which indicates that rare-earth elements play an impor-tant role in superconductivity. [9,10] As is known, 12242 systems have a unique double Fe2As2 layer (named interlayer and intralayer), which comes from the corresponding Fe2As2 layer of the parent 1111 and 122 iron-based superconductors. [11] It appears that the spacing between the bilayers increases with the increasing radius of the lanthanum ion, but in fact it is the lattice mismatch [12,13] that really affects the variation of the spacing in the bilayer.…”