Superconductivity at 35 K by self doping in RbGd₂Fe₄As₄O₂

Abstract

We report synthesis, crystal structure and physical properties of a novel quinary compound RbGdFeAsO. The new iron oxyarsenide is isostructural to the fluo-arsenide KCaFeAsF, both of which contain separate double FeAs layers that are self hole-doped in the stoichiometric composition. Bulk superconductivity at [Formula: see text] K is demonstrated by the measurements of electrical resistivity, dc magnetic susceptibility and heat capacity. An exceptionally high value of the initial slope of the upper critical field ([Formula: see text]d[Formula: see text]/d[Formula: see text] [Formula: see text] T K) is measured for the polycrystalline sample.

Superconductivity at 33–37 K in ALn2Fe4As4O2 (AWu1, Wang2, He3 et al. 2017Phys. Rev. MaterialsSelf Cite382221View full textAdd to dashboardCite

“…Samples of ALn 2 Fe 4 As 4 O 2 (Ln = Gd, Tb, Dy, Ho for A = K; Ln = Nd, Sm, Gd, Tb, Dy, Ho for A = Cs) were synthesized via solid state reaction processes similar to the previously reported KCa 2 Fe 4 As 4 F 2 13 . First, source materials of Fe powder (99.998%) and Ln powder (99.9%) were respectively mixed with As granule (99.999%), sealed in evacuated quartz tubes, and heated to 750 • C to prepare FeAs, Fe 2 As, and LnAs.…”

“…12 The T c values are 30.5 K and 28.2 K, respectively. Then we also succeeded in synthesizing the first 12442-type oxyarsenide, RbGd 2 Fe 4 As 4 O 2 , whose T c achieves 35 K. 13 With the substitution of rare-earth elements, four additional oxyarsenides in the Rb-containing series have been found. 14 These studies show that the lattice match between 122 and 1111 blocks is important, as suggested in our earlier proposal.…”

Growth, properties and magnetism of CaKFe4As4

“…In all four of these examples, the species above and below an Fe-As sheet are the same, preserving the glide-symmetry across the Fe plane. [26,27], AR 2 Fe 4 As 4 O 2 (Ae = Ca, Sr, Ba, Eu; A = K, Rb, Cs; R = lanthanide) [28,29,30] ]. In these families, two different alternating layers separate the Fe-As sheets.…”

Critical Current Density and Vortex Dynamics in Pristine and Irradiated KCa2Fe4As4F2

“…This is in contrast to quasi two-dimensional electronic states in cuprate superconductors with two-dimensional CuO 2 layers [3,4]. Recently, however, it was suggested that quasi two-dimensional electronic states emerge in novel IBSs, such as 12442-type compounds [5][6][7][8][9] or some IBSs consisting of FeSe layers sandwiched by thick insulating layers [10,11]. The 12442-type IBSs have double Fe 2 As 2 conducting layers between two neighboring Ca 2 F 2 insulating layers [5].…”