The Layered Iron Arsenide Oxides Sr₂CrO₃FeAs and Ba₂ScO₃FeAs

Abstract

Abstract. The iron arsenide oxides Sr 2 CrO 3 FeAs and Ba 2 ScO 3 FeAs were synthesized by high temperature solid state reactions and their crystal structures determined by the X-ray powder diffraction. Their structures are tetragonal (P4/nmm; Sr 2 CrO 3 FeAs: a = 391.12(1) pm, c = 1579.05(3) pm; Ba 2 ScO 3 FeAs: a = 412.66(5) pm, c = 1680.0(2) pm, Z = 2) and isotypic to Sr 2 GaO 3 CuS. Iron arsenide layers are sandwiched between perowskite-like metal oxide layers and separated by ~1600 pm, which is much larger compared to the ZrCuSiAs-type '1111' iron arsenide superconductors. The bond lengths and angles within the FeAs layers are adapted to the space requirements of the oxide blocks. Measurements of the magnetic susceptibility, electrical resistivity and temperature-dependent crystal structure show no hint for a structural phase transition or magnetic anomaly in both compounds. Sr 2 CrO 3 FeAs shows Curie-Weiss paramagnetism above 160 K with an effective magnetic moment of 3.83(3) µ B in good agreement with the theoretical value of 3.87 µ B for Cr 3+ (S = 3/2).

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

“…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).…”

Superconductivity Above 40 K Observed in a New Iron Arsenide Oxide (Fe2As2)(Ca4(Mg,Ti)3Oy)

“…Among them, a series of pnictide oxides having perovskite-type blocking layers [2][3][4][5][6][7][8][9][10] are attractive because of their highly two dimensional crystal structure and chemical and structural flexibility at the blocking layers. The latter feature may lead to discoveries of new superconducting materials.…”

Electronic band structure and Fermi surface of new low-temperature Ni-based superconductors: 3.3K (Ni2P2)(Sr4Sc2O6) and 2.7K (Ni2As2)(Sr4Sc2O6) from first principles

“…So, superconductivity was found in (Fe 2 P 2 )(Sr 4 Sc 2 O 6 ) at 17K [15] and in (Fe 2 As 2 )(Sr 4 V 2 O 6 ) at 37K-46K [16,17]. Thus, this family opened up new guidelines for the development of [15,18], Cr [18][19][20], V [16,17], and Mg-Ti [21,22] has been prepared. Another remarkable feature of these perovskite-like oxide blocks is high structural flexibility: their thickness can be controlled according to the composition and synthesis conditions.…”