Superconductivity at 17 K in (Fe₂P₂)(Sr₄Sc₂O₆): a new superconducting layered pnictide oxide with a thick perovskite oxide layer

Abstract

A new layered oxypnictide (Fe 2 P 2 )(Sr 4 Sc 2 O 6 ) have been synthesized by solid-state reaction. This material has an alternating layer stacking structure of anti-fluorite Fe 2 P 2 and perovskite-based Sr 4 Sc 2 O 6 oxide layers. Space group of the material is P4/nmm and lattice constants a and c are 4.016 Å and 15.543 Å, respectively. The interlayer Fe-Fe distance corresponding to the c-axis length is the longest ever reported in the iron-based oxypnictide systems. In both magnetization and resistivity measurements, the present compound exhibited superconductivity below 17 K, which is much higher than that of LaFePO and the highest in arsenic-free iron-based oxypnictide systems under ambient pressure.

Magnetic and electrical properties and carrier doping effects on the iron-based host compound Sr2ScFeAsO3

“…Taking an overview of the Fe-based compounds, Sr 4 Sc 2 Fe 2 P 2 O 6 has distant feature of the Fe 2 P 2 layers and indeed shows the highest T c of 17 K in the As-free Fe-based oxypnictides [16]. The structure of Sr 4 Sc 2 Fe 2 P 2 O 6 consists of the perovskite-realted Sr 2 ScO 3 layers and the Fe 2 P 2 layers, alternatively stacking up [17,18].…”

“…Although many Fe-based compounds contain the perovskite-related layers, such as A 3 M 2 Fe 2 (As,P) 2 O 5 [16,19] and A 4 M 2 Fe 2 (As,P) 2 O 6 [20][21][22][23] (A = Ca, Sr, Ba, M = Sc, V, Cr), only 2 members Sr 4 Sc 2 Fe 2 P 2 O 6 [16] and Sr 4 V 2 Fe 2 As 2 O 6 [20] are superconducting (T c is 17 K and 37 K, respectively) as far as we know. It appears that progress of studies of the distant Fe 2 As 2 layered systems seems to be much behind that of the studies of the intensely coupled Fe 2 As 2 layered systems such as the doped LnFeAsO (Ln = rare-earth element) and AFe 2 As 2 (A = Ca, Sr, Ba).…”

Effect of Fe excess on structural, magnetic and superconducting properties of single-crystalline Fe1+xTe1−ySey

“…layers of almost ideal PbO-like tetrahedra (see [3] for a review and references therein). To date, five families of Febased superconductors have been found: REOFeAs, ("1111", RE=rare earth) [1], AFe 2 As 2 ("122", A=alkaline earth) [4], LiFeAs ("111") [5], Fe(Se,Ch) ("11", Ch=S, Te) [6,7] and the most recently discovered "21311" family of Sr 2 MO 3 FePn (M=Sc,V,Cr and Pn=pnictogen) [8]. Most of the undoped compounds of these families undergo a magnetic transition at low temperature, accompanied by a concomitant structural one, either at the same or slightly higher temperature [3,9].…”

Superconductivity induced by doping platinum inBaFe2As2

“…Many new structures with the FeAs layers have been found, including the so-called 1111 phase (LNFeAsO, AEFeAsF, LN = rare earth elements, AE = alkaline earth elements) [1][2][3] , 122 phase (AEF e 2 As 2 , AE = alkaline earth elements) 4,5 , 111 phase (LiFeAs, NaFeAs) 6,7 , 11 phase (FeSe) 8 , 32522 phase (Sr 3 Sc 2 O 5 Fe 2 As 2 ) 9 , and 21311 phase (Sr 2 ScO 3 FeP and Sr 2 VO 3 FeAs ) 10,11 . In the system of (Ba,Sr) 1−x K x Fe 2 As 2 with the ThCr 2 Si 2 structure (denoted as 122 phase), the maximum T c at about 38 K was discovered 4,5 at about x = 0.40.…”