DOCSLIB.ORG

Download Material for Temporary Copying Purposes Only, Provided These Uses Are for Noncommercial Personal Purposes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Download Material for Temporary Copying Purposes Only, Provided These Uses Are for Noncommercial Personal Purposes Durham Research Online Deposited in DRO: 06 May 2015 Version of attached le: Other Peer-review status of attached le: Peer-reviewed Citation for published item: McCabe, E. E. and Wills, A. S. and Chapon, L. and Manuel, P. and Evans, J. S. O. (2014) 'Structural and magnetic characterization of iron oxyselenides Ce2O2Fe2OSe2 and Nd2O2Fe2OSe2.', Physical review B., 90 (16). p. 165111. Further information on publisher's website: http://dx.doi.org/10.1103/PhysRevB.90.165111 Publisher's copyright statement: Reprinted with permission from the American Physical Society: Physical Review B 90, 165111 c 2014 by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society. Additional information: Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full DRO policy for further details. Durham University Library, Stockton Road, Durham DH1 3LY, United Kingdom Tel : +44 (0)191 334 3042 | Fax : +44 (0)191 334 2971 https://dro.dur.ac.uk Structural and magnetic characterisation of iron oxyselenides Ce2O2Fe2OSe2 and Nd2O2Fe2OSe2 E. E. McCabe,1, 2 A. S. Wills,3 L. Chapon,4, 5 P. Manuel,5 and J. S. O. Evans2 1School of Physical Sciences, University of Kent, Canterbury, CT2 7NH, UK 2Department of Chemistry, Durham University, Durham DH1 3LE, UK 3Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK 4Diffraction Group, Institute Laue Langevin, 71 avenue des Martyrs, 38000 Grenoble, France 5ISIS Facility, Rutherford Appleton Labs, Chilton Didcot, OX11 0QX, UK (Dated: October 21, 2014) We present here an investigation of the magnetic ordering in the Mott insulating oxyselenide materials Ln2O2Fe2OSe2 (Ln = Ce, Nd). Neutron powder diffraction data are consistent with a non-collinear multi-k ordering on the iron sublattice structure and analysis indicates a reduced 2+ 3+ magnetic correlation length perpendicular to the [Fe2O] layers. The magnetic role of the Ln cations is investigated and Ce3+ moments are found to order for T ≤ 16 K. ◦ 1. INTRODUCTION J20 180 Fe { O { Fe interactions) are fully satisfied. In- terestingly, a similar 2-k model, composed of perpendicu- lar AFM chains, has been predicted for the FeAs sheets in The discovery of iron-based superconductivity [1] in iron arsenides and oxyarsenides [27, 28]. The recent stud- several mixed anion systems has driven research to un- ies on La O Fe OSe indicated the presence of antiphase derstand the magnetism of these materials which is 2 2 2 2 boundaries or stacking faults perpendicular to the stack- related to their superconducting behaviour [2]. The ing direction and gave evidence for 2D-Ising-like mag- 1111 family of iron-based superconductors derive from netism within these sheets [25]. In the light of this work, LnFeAsO (Ln = trivalent lanthanide) and adopt the it is timely to report a similar analysis on Ln O Fe OSe ZrCuSiAs-structure [3], composed of alternating layers 2 2 2 2 (Ln = Ce, Nd) analogues to test the robustness of the of anti-fluorite-like edge-linked FeAs tetrahedra alter- 4 2-k model to changes in Fe { O bond lengths and to a nating with fluorite-like edge-linked OLn tetrahedra. 4 magnetic moment on the Ln site. We show that neutron Although the superconductivity arises in the iron ar- powder diffraction (NPD) data are consistent with the senide layers, the Ln3+ cation has a significant role in proposed 2-k magnetic structure and that much larger both tuning the superconducting T in the doped mate- c magnetic stacking domains are formed with these smaller rials [1, 4] and in defining the magnetism of the par- magnetic lanthanides. In contrast with previous work ent non-superconducting materials (such as the spin- [10], we show that Ce moments order at low tempera- reorientations in NdFeAsO [5] and PrFeAsO [6]). This tures and that unlike many related oxyarsenide systems, has led to much research into the interplay between tran- this Ce moment ordering does not cause a reorientation sition metal and lanthanide magnetic sublattices in these of the Fe2+ moments. and related mixed-anion systems [7{19]. La2O2Fe2OSe2 was the first reported member of the \M2O" (M = transition metal) family of oxyselenide 2. EXPERIMENTAL DETAILS materials and adopts a layered structure with fluorite- 2+ like [La2O2] slabs (analogous to those in 1111 iron 5 g each of Ce2O2Fe2OSe2 and Nd2O2Fe2OSe2 were 2− 2+ oxyarsenides) separated by Se anions from [Fe2O] prepared by solid state reaction of CeO2 (Alfa-Aesar, 2+ sheets (Figure 1) [20]. The Fe cations are coordi- 99.8%) or Nd2O3 (Electronic Materials, 99%), Fe nated by two O(2) ions within these anti-CuO2 sheets, (Aldrich, 99.9%) and Se (Alfa Aesar, 99.999%) pow- 2− and by four Se ions above and below the sheets, form- ders. For Nd2O2Fe2OSe2, stoichiometric quantities of arXiv:1410.4990v1 [cond-mat.str-el] 18 Oct 2014 ing a network of face-shared FeO2Se4 trans octahedra. these reagents were intimately ground by hand using Much research has been carried out to understand the an agate pestle and mortar. The resulting grey pow- exchange interactions and magnetic ordering present in der was pressed to form several pellets of 5 mm di- 2+ these [Fe2O] sheets [21]. La2O2Fe2OSe2 orders antifer- ameter. These were placed inside a quartz tube which romagnetically (AFM) below ∼ 90 K [22] and two mag- was evacuated and sealed. This was then heated slowly netic structures have been discussed: a 2-k model first to 1000◦C, held at this temperature for 12 hours and proposed for Nd2O2Fe2OSe2 [23] and a collinear model then cooled in the furnace. For Ce2O2Fe2OSe2, a sto- [10, 22]. Recent work suggests that the 2-k model is the ichiometric mixture of reagents were ground together more likely [24{26]. In this magnetic structure (Figure and pressed into pellets which were placed in a quartz 1), both next-nearest-neighbour (nnn) interactions (fer- tube with an oxygen-getter (Al powder in 10% excess ◦ romagnetic J2 ∼ 95 Fe { Se { Fe interactions, and AFM which was physically isolated from the reagents). This 2 1a) 1b) 1e) J O Se a 2’ Fe J La 2 O(1) Se J1 Fe O(2) b 1c) 4.10 La 4.08 Ce 4.06 / Å / Pr a 4.04 Nd 4.02 4.00 1.10 1.12 1.14 1.16 Ln3+ cation radius 1d) 18.60 Series1 EEM249e_1La EEM249e_2 Cava 18.50 Ce / Å / Pr c Nd 18.40 18.30 1.10 1.12 1.14 1.16 Ln3+ cation radius 2− 2− 2+ 3+ FIG. 1. [color online] a) nuclear cell of Ln2O2Fe2OSeSeries12 with O , Se EEM249e_1, Fe and Ln ions in red, yellow, blue and green, 2+ respectively, showing [Ln2O2] fluorite-like layers built from edge-shared OLn4 tetrahedra in red; b) shows the in-plane arrangement of magnetic moments for the 2-k model, with O2− (red) Se2− (yellow) and Fe2+ (blue) ions shown, and Fe2+ moments shown by blue arrows; the three intraplanar exchange interactions J1, J2 and J20 are also shown; c) and d) show plots of unit cell parameters a and c for Ln2O2Fe2OSe2 determined from Rietveld analysis using room temperature XRPD data (data in blue are described in this work including quench-cooled Ce2O2Fe2OSe2); data in red are determined for the main ( ) and secondary (×) phases in two phase samples of \Ce2O2Fe2OSe2"; green points are those reported for Ce2O2Fe2OSe2 by Ni et al [10]); e) illustrates the magnetic ordering of Ce (green) and Fe (blue) moments (O(1) sites are omitted for clarity). tube was evacuated, sealed, slowly heated to 1000◦C followed by a further five on warming to 300 K. Rietveld and held at this temperature for 12 hours. The reac- refinements [29] were performed using Topas Academic tion tube was then quenched into a bucket of iced water. software [30, 31]. Sequential refinements were controlled ◦ Both Ce2O2Fe2OSe2 and Nd2O2Fe2OSe2 were formed as using local subroutines. The high d-spacing 59 bank of black, polycrystalline powders. Preliminary structural data (10.5 { 85.0 ms, 1 { 8 A)˚ was used to study the mag- characterisation was carried out using a Bruker D8 Ad- netic behaviour of the two materials. The nuclear and vance diffractometer fitted with a LynxEye silicon strip magnetic refinements were carried out with separate nu- detector (step size 0.021◦) operating in reflection mode clear and magnetic phases (lattices parameters and scale with Cu Kα radiation. NPD data were collected on the factor of the magnetic phase were constrained to be mul- time of flight (TOF) diffractometer WISH on target sta- tiples of the nuclear phase). Magnetic susceptibility was tion 2 at the ISIS spallation neutron source. The powders measured using a Magnetic Properties Measurement Sys- were placed in cylindrical 6 mm diameter vanadium cans tem (Quantum Design, MPMS). Field-cooled and zero- (to heights of ∼6 cm). For Ce2O2Fe2OSe2, 16 minute field-cooled data were collected on warming from 2 K (10 µA h) scans were collected every 4 K on cooling from to 292 K at 5 K intervals in an applied magnetic field 120 K to 8 K and a final 25 minute (15 µA h) scan was of 1000 Oe.
Load more

Recommended publications
  • Structure-Property Relationships of Layered Oxypnictides
    AN ABSTRACT OF THE DISSERTATION OF Sean W. Muir for the degree of Doctor of Philosophy in Chemistry presented on April 17, 2012. Title: Structure-property Relationships of Layered Oxypnictides Abstract approved:______________________________________________________ M. A. Subramanian Investigating the structure-property relationships of solid state materials can help improve many of the materials we use each day in life. It can also lead to the discovery of materials with interesting and unforeseen properties. In this work the structure property relationships of newly discovered layered oxypnictide phases are presented and discussed. There has generally been worldwide interest in layered oxypnictide materials following the discovery of superconductivity up to 55 K for iron arsenides such as LnFeAsO1-xFx (where Ln = Lanthanoid). This work presents efforts to understand the structure and physical property changes which occur to LnFeAsO materials when Fe is replaced with Rh or Ir and when As is replaced with Sb. As part of this work the solid solution between LaFeAsO and LaRhAsO was examined and superconductivity is observed for low Rh content with a maximum critical temperature of 16 K. LnRhAsO and LnIrAsO compositions are found to be metallic; however Ce based compositions display a resistivity temperature dependence which is typical of Kondo lattice materials. At low temperatures a sudden drop in resistivity occurs for both CeRhAsO and CeIrAsO compositions and this drop coincides with an antiferromagnetic transition. The Kondo scattering temperatures and magnetic transition temperatures observed for these materials can be rationalized by considering the expected difference in N(EF)J parameters between them, where N(EF) is the density of states at the Fermi level and J represents the exchange interaction between the Ce 4f1 electrons and the conduction electrons.
    [Show full text]
  • Synthesis, Structure and Properties of Layered Phosphide Nitrides Akth2mn4p4n2 (Ak = Rb, Cs)
    Synthesis, structure and properties of layered phosphide nitrides AkTh2Mn4P4N2 (Ak = Rb, Cs) Bai-Zhuo Li,a Si-Qi Wu,a Zhi-Cheng Wang,a Cao Wang,b and Guang-Han Cao*,a,c a Department of Physics, Zhejiang Province Key Laboratory of Quantum Technology and Devices, Interdisciplinary Center for Quantum Information, and State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027, China b School of Physics & Optoelectronic Engineering, Shandong University of Technology, Zibo 255000, China c Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, China Keywords Intercalations | Synthetic methods | Physical properties | Phosphide nitrides | Electronic structures Main observation and conclusion We report the design, synthesis, structure, and properties of two complex layered phosphide nitrides, AkTh2Mn4P4N2 (Ak = Rb, Cs), which contain anti-fluorite-type [Mn2P2] bilayers separated by fluorite-type [Th2N2] layers as a result of the intergrowth between AkMn2P2 and ThMnPN. The new compounds are featured with an intrinsic hole doping associated with the interlayer charge transfer and a built-in chemical pressure from the [Th2N2] layers, both of which are reflected by the changes in the lattice and the atomic position of phosphorus. The measurements of magnetic susceptibility, electrical resistivity, and specific heat indicate existence of local moments as well as itinerant electrons in relation with d-p hybridizations. The expected dominant antiferromagnetic interactions with enhanced d-p hybridizations were demonstrated by the first-principles calculations only when additional Coulomb repulsions are included. The density of states at the Fermi level derived from the specific-heat analysis are 3.5 and 7.5 times of the calculated ones for Ak = Rb and Cs, respectively, suggesting strong electron correlations in the title compounds.
    [Show full text]
  • Download Article (PDF)
    Z. Kristallogr. 226 (2011) 435–446 / DOI 10.1524/zkri.2011.1363 435 # by Oldenbourg Wissenschaftsverlag, Mu¨nchen Structural chemistry of superconducting pnictides and pnictide oxides with layered structures Dirk JohrendtI, Hideo HosonoII, Rolf-Dieter HoffmannIII and Rainer Po¨ttgen*, III I Department Chemie und Biochemie, Ludwig-Maximilians-Universita¨t Mu¨nchen, Butenandtstraße 5–13 (Haus D), 81377 Mu¨nchen, Germany II Frontier Research Center, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan III Institut fu¨r Anorganische und Analytische Chemie, Universita¨t Mu¨nster, Corrensstraße 30, 48149 Mu¨nster, Germany Received October 29, 2010; accepted February 6, 2011 Pnictide / Pnictide oxide / Superconductivity / for hydride formation of CeRuSi ! CeRuSiH [6] and Intermetallics / Group-subgroup relation CeRuGe ! CeRuGeH [7]. The crystal chemical data of the huge number of ZrCuSiAs materials have recently Abstract. The basic structural chemistry of supercon- been reviewed [8]. ducting pnictides and pnictide oxides is reviewed. Crystal Although the basic crystallographic data of the many chemical details of selected compounds and group sub- ThCr2Si2 and ZrCuSiAs type compounds are known for group schemes are discussed with respect to phase transi- several years, especially for the ZrCuSiAs family, systema- tions upon charge-density formation, the ordering of va- tic property studies have been performed only recently. cancies, or the ordered displacements of oxygen atoms. These investigations mainly focused on p-type transparent Furthermore, the influences of doping and solid solutions semiconductors like LaCuSO (for a review see [9]) or the on the valence electron concentration are discussed in or- colored phosphide and arsenide oxides REZnPO [10] and der to highlight the structural and electronic flexibility of REZnAsO [11].
    [Show full text]
  • STRUCTURAL, ELECTRONIC PROPERTIES and the FEATURES of CHEMICAL BONDING in LAYERED 1111-OXYARSENIDES Larhaso and Lairaso: AB INITIO MODELING
    The preprint. Submitted to: Journal of Structural Chemistry STRUCTURAL, ELECTRONIC PROPERTIES AND THE FEATURES OF CHEMICAL BONDING IN LAYERED 1111-OXYARSENIDES LaRhAsO AND LaIrAsO: AB INITIO MODELING V.V. Bannikov, I.R. Shein Institute of Solid State Chemistry, Ural Branch Of Russian Academy of Sciences, 620990, Ekaterinburg, Pervomayskaya St., 91, Russia E-mail: [email protected] The comparative study of structural, electronic properties, topology of the Fermi surface, and the features of chemical bonding in layered 1111-oxyarsenides LaRhAsO and LaIrAsO has been performed based on the results of ab initio modeling of their electronic structure. It was established that only weak sensitivity with respect both to electron and hole doping is expected for LaIrAsO being non-magnetic metal, however, the Rh-containing compound should be characterized with weak band magnetism, and the hole doping is expected to be able to move its ground state away from the boundary of magnetic instability. The mentioned feature allows to consider LaRhAsO oxyarsenide as a possible “electron analogue” of LaFeAsO compound being the initial phase for the layered FeAs-superconductors. Keywords: 1111-phases, oxyarsenides, doping, band structure, Fermi surface, chemical bonding INTRODUCTION The oxychalcogenides and oxypnictides with common chemical formula Me(a)Me(b)(Ch/Pn)O (where Me(a) is atom of Y, La, Bi or 4f-metal, usually taking the oxidation state +3 in compounds, Me(b) is atom of d-metal, Ch = S, Se, Te, Pn = P, As, Sb) form the vast family of so-called layered 1111-phases [1,2] with tetragonal ZrCuSiAs-like structure which can be regarded as the sequence of [Me(a)–O] and [Me(b)–(Ch/Pn)] blocks alternating along the tetragonal axis, where each atom is characterized with coordination number = 4 (Fig.1).
    [Show full text]
  • On the New Oxyarsenides Eu5zn2as5o and Eu5cd2as5o
    crystals Article On the New Oxyarsenides Eu5Zn2As5O and Eu5Cd2As5O Gregory M. Darone 1,2, Sviatoslav A. Baranets 1,* and Svilen Bobev 1,* 1 Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA; [email protected] 2 The Charter School of Wilmington, Wilmington, DE 19807, USA * Correspondence: [email protected] (S.B.); [email protected] (S.A.B.); Tel.: +1-302-831-8720 (S.B. & S.A.B.) Received: 20 May 2020; Accepted: 1 June 2020; Published: 3 June 2020 Abstract: The new quaternary phases Eu5Zn2As5O and Eu5Cd2As5O have been synthesized by metal flux reactions and their structures have been established through single-crystal X-ray diffraction. Both compounds crystallize in the centrosymmetric space group Cmcm (No. 63, Z = 4; Pearson symbol oC52), with unit cell parameters a = 4.3457(11) Å, b = 20.897(5) Å, c = 13.571(3) Å; and a = 4.4597(9) Å, b = 21.112(4) Å, c = 13.848(3) Å, for Eu5Zn2As5O and Eu5Cd2As5O, respectively. The crystal structures include one-dimensional double-strands of corner-shared MAs4 tetrahedra (M = Zn, Cd) and As–As bonds that connect the tetrahedra to form pentagonal channels. Four of the five Eu atoms fill the space between the pentagonal channels and one Eu atom is contained within the channels. An isolated oxide anion O2– is located in a tetrahedral hole formed by four Eu cations. Applying the valence rules and the Zintl concept to rationalize the chemical bonding in Eu5M2As5O(M = Zn, Cd) reveals that the valence electrons can be counted as follows: 5 [Eu2+] + 2 [M2+] + 3 × × × [As3–] + 2 [As2–] + O2–, which suggests an electron-deficient configuration.
    [Show full text]
  • Crystal Structure of the New Fese1àx Superconductorw
    View Article Online / Journal Homepage / Table of Contents for this issue COMMUNICATION www.rsc.org/chemcomm | ChemComm Crystal structure of the new FeSe1Àx superconductorw Serena Margadonna,*a Yasuhiro Takabayashi,b Martin T. McDonald,b Karolina Kasperkiewicz,a Yoshikazu Mizuguchi,c Yoshihiko Takano,c Andrew N. Fitch,d Emmanuelle Suarde and Kosmas Prassides*b Received (in Cambridge, UK) 29th July 2008, Accepted 5th September 2008 First published as an Advance Article on the web 26th September 2008 DOI: 10.1039/b813076k The newly discovered superconductor FeSe1Àx (x E 0.08, extremely sensitive to applied pressure and rises rapidly at a onset À1 9 Tc E 13.5 K at ambient pressure rising to 27 K at rate of 9.1 K GPa , reaching a value of 27 K at 1.48 GPa. 1.48 GPa) exhibits a structural phase transition from tetragonal a-FeSe crystallises at room temperature with the tetragonal to orthorhombic below 70 K at ambient pressure—the crystal PbO-type structure (Fig. 1) and comprises stacks of edge- structure in the superconducting state shows remarkable sharing FeSe4 tetrahedra—the FeSe packing motif is similarities to that of the REFeAsO1ÀxFx (RE = rare earth) essentially identical to that of the FeAs layers in the iron superconductors. oxyarsenides. On cooling, it was reported that a structural phase transition occurs near 105 K to an unidentified Superconductivity at the surprisingly high temperature of low-temperature structure with possible triclinic symmetry.8 55 K has been recently reported in fluorine-doped rare-earth At present, little else is known about the electronic properties 1 iron oxyarsenides, REFeAsO1ÀxFx.
    [Show full text]
  • Mag Lab Reports, Volume 15, Issue 3
    VOLUME 15 • NO. 3 NATIONAL HIGH MAGNETIC FIELD LABORATORY MAG LAB REPORTS FLORIDA STATE UNIVERSITY · UNIVERSITY OF FLORIDA · LOS ALAMOS LAB • New family of superconductors raises exciting possibilities, results for researchers Page 5 • Love connection: How C. elegans find their mates Page 13 VOLUME 15 • No. 3 Table of contents 3 From the Director’s Desk 5 Research suggest novel superconductors are in a class all their own 8 Stanford, Mag Lab collaborate to glean data on magnetic order in Ba3Mn2O8 10 Examining quadrupolar nuclei with high magnetic fields 13 Mate or hibernate? How C. elegans answer that question 16 ICR looks ahead to next-generation FT-ICR mass spectrometer 18 Summer of science: multiple outreach initiatives close successfully 20 People in the news 22 Steve Hill selected as EMR director 23 Science Starts Here: Chris Ramsey Trying to reduce your carbon footprint? Sign up for an online subscription at http://www/ mediacenter/publications/ subscribe.aspx On the cover: A new family of superconductors known as doped rare-earth iron oxyarsenides or oxypnictides has come under increasing focus from the research community. Learn more on page 5. Published by: National High Magnetic Field Laboratory 1800 East Paul Dirac Drive Director: GREG BOEBINGER This document is available in alternate Tallahassee, Florida 32310-3706 formats upon request. If you would like to be Associate Director for Management added to our mailing list, please write Amy and Administration: BRIAN FAIRHURST Mast at the address shown at left, call 850 Tel: 850 644-0311 Director, Public Affairs: SusaN RaY 644-1933, or e-mail [email protected].
    [Show full text]
  • Inelastic Neutron Scattering Studies of Magnetic Fluctuations in the Tetragonal and Collapsed Tetragonal Phases of Cafe2as2
    Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2013 Inelastic neutron scattering studies of magnetic fluctuations in the tetragonal and collapsed tetragonal phases of CaFe2As2 Jing Han Soh Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Condensed Matter Physics Commons Recommended Citation Soh, Jing Han, "Inelastic neutron scattering studies of magnetic fluctuations in the tetragonal and collapsed tetragonal phases of CaFe2As2" (2013). Graduate Theses and Dissertations. 13593. https://lib.dr.iastate.edu/etd/13593 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Inelastic neutron scattering studies of magnetic fluctuations in the tetragonal and collapsed tetragonal phases of CaFe2As2 by Jing Han Soh A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Condensed Matter Physics Program of Study Committee: Alan I. Goldman, Major Professor Robert J. McQueeney Lee Anne Willson Duane Johnson Iowa State University Ames, Iowa 2013 Copyright c Jing Han Soh, 2013. All rights reserved. ii TABLE OF CONTENTS LIST OF TABLES . iv LIST OF FIGURES . v ACKNOWLEDGEMENTS . x ABSTRACT . xi CHAPTER 1. Introduction to iron-arsenide based superconductors . 1 1.1 Introduction . .1 1.2 Structure and superconductivity in iron-arsenide superconductors . .3 1.3 CaFe2As2: case study of the 122-family .
    [Show full text]
  • Royal Society of Chemistry 19 – 20 December 2016
    Royal Society of Chemistry Solid State Chemistry Group Christmas Meeting Holywell Park, Loughborough University 19th – 20th December 2016 with thanks to our Gold Sponsors: and our Silver Sponsor: 36th Solid State Chemistry Group Meeting, LOUGHBOROUGH UNIVERSITY 19 – 20 December 2016 Holywell Park: Stephenson Lecture Theatre Monday 19th December 2016: TIME SPEAKER TITLE 12:00 – 13:00 Registration/Lunch/Posters (Carvery Buffet) Chair Dr Pooja Panchmatia 13:00 – 13:05 Dr. Pooja Panchmatia Opening Remarks 13:05 – 14:00 Prof. Aron Walsh Light, Camera, Electrons: Ionisation Potentials of Solids (Imperial) 14:00 – 14:20 Jenny Heath Beyond Lithium? Atomic-Scale Insights into Polyanion Cathode (Bath) Materials for Na+ and Mg2+ Rechargeable Batteries 14:20 – 14:40 Neeraj Sharma Using in situ synchrotron X-ray diffraction to understand the Na (UNSW, Australia) insertion/extraction reactions in the Na3V2O2x(PO4)2F3-2x family 14:40 – 15:00 Zhe Liu A novel polymer-assisted LiBH4 composite material for reversible (Glasgow) hydrogen storage 15:00 – 15:20 Paul Brack Ball milling of ferrosilicon powders and their application in (Loughborough) hydrogen generation 15:20 – 15:50 Break/Posters (Severn Room) Chair Prof. Aron Walsh 15:50 – 16:10 Marco Amores (Glasgow) Fast microwave-assisted synthesis and lithium-ion diffusion studies of lithium stuffed garnets 16:10 – 16:30 Aoifa K. Lucid Force field derivation and modelling of LaGaO3 for solid oxide fuel (Trinity College Dublin) cell electrolytes 16:30 – 16:50 J. Felix Shin Perovskite composite cathodes for
    [Show full text]
  • The Electronic and Magnetic Properties of Magnetoresistant Nd1-Xsrxmnaso Oxyarsenides
    The Electronic and Magnetic Properties of Magnetoresistant Nd1-xSrxMnAsO Oxyarsenides E. J. Wildman 1, N. Emery 2 and A. C. Mclaughlin* 1 1 The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, Scotland. 2 Institut de Chimie et des Materiaux Paris Est, ICMPE/GESMAT, UMR 7182 CNRS-Universite Paris Est Creteil, CNRS 2 rue Henri Dunant, 94320 Thiais, France * [email protected] Abstract The oxypnictides Nd1-xSrxMnAsO have been successfully synthesised with x up to 0.1. A synchrotron X-ray diffraction study demonstrates that there is no change in crystal symmetry upon doping with Sr. An expansion of the inter-layer distance between Nd-O-Nd and As-Mn-As blocks is observed with increasing x. Results from variable temperature neutron diffraction and resistivity measurements show that the local moment antiferromagnetic order of the Mn spins is preserved as the [MnAs]- layers are hole doped and the materials are driven metallic for x 0.05. A sizeable positive magnetoresistance is observed at low temperature which demonstrates that multiple MR mechanisms are possible in LnMnAsO oxypnictides. 1 I. INTRODUCTION Iron oxyarsenides, LnFeAsO, with the tetragonal ZrCuSiAs structure, have recently received much attention due to the observation of high temperature superconductivity. A maximum Tc of 55 K has been achieved via substitution of oxygen with fluorine 1, 2, 3 or by creating oxygen vacancies 4. We have recently investigated the Mn analogue LnMnAsO (Ln = La, Nd) 5, 6. Both materials are 2+ antiferromagnetic with TMn ~ 360 K. Below TMn the Mn moments are aligned antiferromagnetically in the ab plane, but ferromagnetically along c and the moment is ordered parallel to the c axis.
    [Show full text]
  • Arxiv:1704.01441V1 [Cond-Mat.Str-El] 5 Apr 2017 Tronic, Magnetic, and Structural Properties They Possess
    The magnetic and electronic properties of Oxyselenides - influence of transition metal ions and lanthanides C. Stock1 and E. E. McCabe2 1School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, UK 2School of Physical Sciences, University of Kent, Canterbury, CT2 7NH, UK (Dated: October 15, 2018) Magnetic oxyselenides have been a topic of research for several decades, firstly in the context of photoconductivity and thermoelectricity owing to their intrinsic semiconduct- ing properties and ability to tune the energy gap through metal ion substitution. More recently, interest in the oxyselenides has experienced a resurgence owing to the possible relation to strongly correlated phenomena given the fact that many oxyselenides share a similar structure to unconventional superconducting pnictides and chalcogenides. The two dimensional nature of many oxyselenide systems also draws an analogy to cuprate physics where a strong interplay between unconventional electronic phases and localised magnetism has been studied for several decades. It is therefore timely to review the physics of the oxyselenides in the context of the broader field of strongly correlated magnetism and electronic phenomena. Here we review the current status and progress in this area of research with the focus on the influence of lanthanides and transition metal ions on the intertwined magnetic and electronic properties of oxyselenides. The emphasis of the review is on the magnetic properties and comparisons are made with iron based pnictide and chalcogenide systems. CONTENTS 8. Summary of the magnetic structure variation with transition metal ion 21 I. Introduction 1 E. Magnetic interactions 22 1. La2O2Fe2OSe2 and Ce2O2FeSe2 22 2+ 2+ II. Experimental techniques 2 2.
    [Show full text]
  • United States Patent 19 11, 3,748,095 Henderson Et Al
    United States Patent 19 11, 3,748,095 Henderson et al. (45) July 24, 1973 54). PRODUCTION OF HIGH PURITY RARE EARTH SULFDES OTHER PUBLICATIONS E75) Inventors: James R. Henderson, Los Angeles; Eastman et al., "Journal of the American Chemical So Donald M. Johnson, Malibu; Michiya ciety," Vol. 72, 1950, pp. 2248-2250. Muramoto, Santa Monica, all of Samsonov, “High-Temperature Compounds of Rare Calif. Earth Metals with Nonmetals,' Consultants Bureau, 73 Assignee: McDonnell Douglas Corporation, New York, 1965, pp. 252-259. Santa Monica, Calif. 22 Filed: June 17, 1968 Primary Examiner-Carl D. Quarforth Assistant Examiner-F. M. Gittes 21 Appl. No.: 737,770 Attorney-Max Geldin 52 U.S. Cl.................... 423/21, 4231254,423/252, 42313, 4231562 57 ABSTRACT 51) int. Cl........................ C22b 59/00, C01f 17700 Novel method for the production of high purity metal 58 Field of Search ................. 23/50, 53, 134, 204, sulfides, selenides, tellurides, and arsenides, particu 23/21,316, 347, 345, 206 larly those of high melting point greater than 1,000 C, e.g., such compounds of the rare earth metals. An an (56) References Cited hydrous metal, metal salt, metal oxide or mixtures UNITED STATES PATENTS thereof is contacted with a gas mixture, e.g., HS and 3,282,656 1 1/1966 Kruger et al.......................... 23.1347 CS, at a high temperature, e.g., in the range of about 3,334,974 8/1967 Fletcher et al........................ 23/345 1,250° C to about 1,325' C, in the substantial absence 2,980,500 4/1961 Miller............................... 23/134 X of water vapor and oxygen until the product has been 3,033,659 5/1962 Fischer............................
    [Show full text]