Second Homologous Series of Iron Pnictide Oxide Superconductors (Fe2As2)(Can+2(Al,Ti)nOy)[n = 2,3,4]

Abstract

We have discovered a new homologous series of iron pnictide oxides (Fe2As2)(Can+2(Al,Ti)nOy)[n = 2,3,4]. These compounds have perovskite-like blocking layers between Fe2As2 layers. The structure of new compounds are tetragonal with space groups of P4/nmm for n = 2 and 4 and P4mm for n = 3, which are similar to those of (Fe2As2)(Can+1(Sc,Ti)nOy)[n = 3,4,5] found in our previous study. Compounds with n = 3 and 4 have new crystal structures with 3 and 4 sheets of perovskite layers, respectively, including a rock salt layer in each blocking layer. The a-axis lengths of the three compounds are approximately 3.8 A, which are close to those of FeSe and LiFeAs. (Fe2As2)(Ca6(Al,Ti)4Oy) exhibited bulk superconductivity in magnetization measurement with Tc(onset)~36 K and resistivity drop was observed at ~39 K. (Fe2As2)(Ca5(Al,Ti)3Oy) also showed large diamagnetism at low temperatures. These new compounds indicate considerable rooms are still remaining for new superconductors in layered iron pnictides.

10 pages, 5 figures

References in corpus (6)

• Superconductivity at 17 K in (Fe2P2)(Sr4Sc2O6): a new superconducting layered pnictide oxide with a thick perovskite oxide layer
• (Sr_3Sc_2O_5)Fe_2As_2 as a possible parent compound for FeAs-based superconductors
• First Homologous Series of Iron Pnictide Oxide Superconductors (Fe2As2)(Can+1(Sc,Ti)nOy) [n = 3,4,5] with Extremely Thick Blocking Layers
• New iron-based arsenide oxides (Fe2As2)(Sr4M2O6)(M = Sc, Cr)
• Superconductivity Above 40 K Observed in a New Iron Arsenide Oxide (Fe2As2)(Ca4(Mg,Ti)3Oy)
• New Iron Arsenide Oxides (Fe2As2)(Sr4(Sc,Ti)3O8), (Fe2As2)(Ba4Sc3O7.5), and (Fe2As2)(Ba3Sc2O5)

Cited by in corpus (11)

• Iron based high transition temperature superconductors
• Superconductivity at 28.3 and 17.1 K in (Ca4Al2O6-y)(Fe2Pn2) (Pn = As and P)
• Maximizing Fermi surface multiplicity optimizes superconductivity in iron pnictides
• Superconducting Transition Temperatures of up to 47 K from Simultaneous Rare-Earth Element and Antimony Doping of 112-Type CaFeAs2
• Transport Properties and Electronic Phase Diagram of Single-Crystalline Ca${}_{10}$(Pt${}_3$As${}_8$) ((Fe${}_{1-x}$Pt${}_x$)${}_2$As${}_2$)${}_5$
• Electronic Structure of Novel Superconductor Ca4Al2O6Fe2As2
• Iron-platinum-arsenide superconductors Ca10(PtnAs8)(Fe2-xPtxAs2)5
• Crystal growth and phase diagram of 112-type iron pnictide superconductor Ca1-yLayFe1-xNixAs2
• NMR Investigation of the iron-based superconductors Ca4(Mg,Ti)3Fe2As2O8-y and Ca5(Sc,Ti)4Fe2As2O11-y
• Anisotropies and Homogeneities of Superconducting Properties in Iron-Platinum-Arsenide Ca10(Pt3As8)(Fe1.79Pt0.21As2)5
• Synchrotron X-ray Diffraction Study of Structural Phase Transition in Ca10(Ir4As8)(Fe2-xIrxAs2)