DOCSLIB.ORG

Revising the Common Understanding of Metamagnetism in the Molecule-Based Bisdithiazolyl Bdtme Compound

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Revising the Common Understanding of Metamagnetism in the Molecule-Based Bisdithiazolyl Bdtme Compound PCCP View Article Online PAPER View Journal | View Issue Revising the common understanding of metamagnetism in the molecule-based Cite this: Phys. Chem. Chem. Phys., 2019, 21,12184 bisdithiazolyl BDTMe compound† ab ac ad Cla`udia Climent, Sergi Vela, Joaquim Jornet-Somoza and a Merce` Deumal * The BDTMe molecule-based material is the first example of a thiazyl radical to exhibit metamagnetic behavior. Contrary to the common idea that metamagnetism occurs in low-dimensional systems, it is found that BDTMe magnetic topology consists of a complex 3D network of almost isotropic ferromagnetic spin-ladders that are coupled ferromagnetically and further connected by some weaker antiferromagnetic interactions. Calculated magnetic susceptibility wT(T) data is in agreement with experiment. Calculated M(H) data clearly show the typical sigmoidal shape of a metamagnet at temperatures below 2 K. The calculated critical field becomes more apparent in the dM/dH(H) plot, being in very good agreement with experiment. Our Creative Commons Attribution-NonCommercial 3.0 Unported Licence. computational study concludes that the magnetic topology of BDTMe is preserved throughout the entire experimental range of temperatures (0–100 K). Accordingly, the ground state is the same irrespective of the temperature at which we study the BDTMe crystal. Revising the commonly accepted understanding of a metamagnet explained as ground state changing from antiferromagnetic to ferromagnetic, the Boltzmann population of the different states is here suggested to be the key concept: at 2 K the ground Received 24th January 2019, singlet state has more weight (24%) than at 10 K (1.5%), where excited states have an important role. Accepted 14th May 2019 Changes in the antiferromagnetic interactions that couple the ferromagnetic skeleton of BDTMe will DOI: 10.1039/c9cp00467j directly affect the population of the distinct states that belong to a given magnetic topology and thus its This article is licensed under a magnetic response. Accordingly, this strategy could be valid for a wide range of bisdithiazolyl BDT- rsc.li/pccp compounds whose magnetism can be tuned by means of weak antiferromagnetic interactions. Open Access Article. Published on 31 May 2019. Downloaded 9/26/2021 4:42:53 PM. Introduction The contemporary challenge to the synthetic chemists is to produce new compounds with pre-assigned magnetic, electrical, New molecular materials with targeted physical properties are an and optical properties and, for this, the rational synthetic design area of current interest from both fundamental and applicative is addressed to tune the solid-state structure. The ability to points of view. Molecule-based magnets exhibit a wide variety of manipulate magnetic coupling and/or charge transfer between bonding and structural motifs. These include one-, two-, and spin carriers is thus the key to creating new multifunctional three dimensional (1D, 2D, and 3D, respectively) network struc- materials.2–4 tures by variation of metal atoms, organic radicals, and ligands.1 Neutral heterocyclic radicals containing sulfur/selenium– nitrogen rings, i.e., heterocyclic thiazyl/selenazyl radicals, play a Seccio´ Quı´mica Fı´sica, Dept. Cie`ncia de Materials i Quı´mica Fı´sica & IQTCUB, important roles in the development of molecule-based functional 5–13 Universitat de Barcelona, Martı´ iFranque`s 1, E-08028 Barcelona, Spain. materials. In fact, there is a long-lasting interest in the charge E-mail: [email protected] transport14–17 and magnetic8,18–20 properties of heterocyclic thiazyl b Departamento de Fı´sica Teo´rica de la Materia Condensada, and selenazyl radicals, as the presence of heavy heteroatoms in Universidad Auto´noma de Madrid, E-28049 Madrid, Spain c Laboratory for Computational Molecular Design (LCMD), Institute of Chemical these systems enhances both intermolecular electronic and 10,21,22 Sciences and Engineering, EPFL, CH-1015 Lausanne, Switzerland magnetic exchange interactions. In such compounds, the d Theory Department, The Max Planck Institute for the Structure and Dynamics of crucial component is the conjugated p-electron system. Specifi- Matter (MPSD), Bldg. 99 (CFEL), Luruper Chaussee 149, 22761 Hamburg, cally, the interactions between the p-systems of the radicals play Germany the key role in determining magnetic and electrical properties. † Electronic supplementary information (ESI) available: Section S1. d1–d10 p isolated pairs of BDTMe radicals. Section S2. Comparison between values of J Therefore, attempts to modulate the -interactions among radicals i 23–27 from our calculations and from ref. 39. Section S3. Discussion on magnetic by crystal engineering have been highly pursued. Within models. See DOI: 10.1039/c9cp00467j this context, the resonance stabilized bisdithiazolyl framework 12184 | Phys. Chem. Chem. Phys., 2019, 21, 12184--12191 This journal is © the Owner Societies 2019 View Article Online Paper PCCP Fig. 1 (a) BDTR1R2 chemical formula, where BDT stands for the C5N3S4 bisdithiazolyl skeleton, R1 =CH3 and R2 = H. (b) BDTMe monomer spin density distribution (isodensity surface = 0.002 a.u.). 28,29 51,52 BDTR1R2 (Fig. 1a) represents an appealing building block. In means of a first-principles bottom-up (FPBU) procedure particular, bisdithiazolyl units have proved to be ideal candidates to using ab initio methods in order to understand its macroscopic address the challenge of building multi-dimensional magnetism in magnetic behavior. Hence we use the standard static approach molecular materials, for which their exposed skeleton allows for for both the interpretation and the simulation of the magnetic intermolecular weak hydrogen bonds and p–p interactions.30 properties of the BDTMe material assuming that these properties Modification of the axial substituents R1/R2 and the incorpora- can be obtained with a single static configuration (an X-ray resolved tion of selenium have provided a wide range of materials structure or, alternatively, an optimized structure). Therefore, using showing both enhanced conductivity12,31–34 and interesting the available X-ray data, we have first characterized the magnetic magnetic properties, such as ferromagnetism, ferrimagnetism, topology of BDTMe in terms of all significant Ji magnetic inter- antiferromagnetism, metamagnetic behavior, and spin-Peierls actions. Surprisingly, the magnetic topology is found to be a three- 32,35–41 transition. dimensional (3D) Ji -network and does not change drastically as a 42–46 Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Former experience in bistable dithiazolyl DTA and multi- function of temperature, i.e. it is preserved irrespective of using the orbital semiquinone-bridged bisdithiazolyl XBBO47 compounds crystallographic data at 35 K or 100 K. We have then calculated triggered us to undertake the study of the bisdithiazolyl com- wT(T)andM(H) and compared our data to experiment in order to pound BDTMe (see Fig. 1a, where R1 =CH3 and R2 =H,whose assess whether the BDTMe system is well described. Finally, the systematic nomenclature is 4-methyl-4H-bis(1,2,3)dithiazolo- study of dM/dH(H) as a function of temperature has shed light to (4,5-b:50,40-e)pyrid-3-yl radical39), since it is the first example of why BDTMe behaves as a metamagnet. a thiazyl radical to exhibit metamagnetic behavior. Metamagnetism is a type of magnetic transition displayed by some low-dimensional systems (e.g. displaying chains or layers as main topological motif) Computational details This article is licensed under a with competing magnetic interactions.48 In a metamagnet, the net moments arising from intra-motif interactions are aligned The first principles bottom-up (FPBU) working strategy follows antiparallel as a result of weak inter-motif antiferromagnetic four steps.51,52 First, one has to select all possible magnetically Open Access Article. Published on 31 May 2019. Downloaded 9/26/2021 4:42:53 PM. (AFM) interactions to give rise to an AFM state. According to relevant pairs of radicals in the crystal by analysis of the crystal Carlin’s book definition of metamagnet, the application of an packing. As for the BDTMe crystal, the pairs of BDTMe radicals external magnetic field can break up the AFM ordering and turn have been chosen in terms of the SÁÁÁS distance, since the spin the system to a ferromagnetic (FM) state without going through a density of this radical is delocalized over S, N and C atoms 48 spin-flop state. The Neel temperature (TN) for AFM ordering (see Fig. 1b). Accordingly, only i dimers (di) of BDTMe radicals and the critical field (HC) for the metamagnetic transition are whose SÁÁÁS distance was shorter than a threshold distance of sensitive to the inter-motif interactions. At this point it is fair to 8 Å were selected. The choice of the BDTMe pairs has been comment that, after metamagnetic transition, we will show that conducted in order to include all exchange interactions that the system does not become a FM state. The key concept is might be magnetically significant.53 instead the competition between AFM and FM interactions that It is then next required the computation of the radical- will directly affect the Boltzmann population of the distinct radical J(di) interaction for each pair of radicals selected in states that belong to the magnetic topology of a given molecular the crystal, referred to as Ji thorough the paper. The micro- material and, thus, its magnetic response. scopic Ji magnetic interaction is evaluated in terms of energy Regarding the BDTMe radical, Oakley and co-workers have differences. The energy calculations were performed at DFT/ reported both magnetic measurements (down to 2 K) and high UB3LYP54,55 level as implemented in Gaussian.56 The standard quality crystal properties (at 35 K, 100 K and 293 K).39,49,50 Early 6-311++G(d,p) basis set57–61 was used in all energy calculations. magnetic susceptibility (w) measurements indicated a signifi- Once all intrinsic Ji exchange couplings have been computed, cant FM surge in wT at low temperatures. In addition, it was one must propose the magnetic topology of the crystal in terms reported that below 5 K the material orders ferromagnetically of all non-negligible Ji magnetic interactions.
Load more

Recommended publications
  • United States Patent Application 20110255645 Kind Code A1 Zawodny; Joseph M
    ( 1 of 1 ) United States Patent Application 20110255645 Kind Code A1 Zawodny; Joseph M. October 20, 2011 Method for Producing Heavy Electrons Abstract A method for producing heavy electrons is based on a material system that includes an electrically-conductive material is selected. The material system has a resonant frequency associated therewith for a given operational environment. A structure is formed that includes a non-electrically-conductive material and the material system. The structure incorporates the electrically-conductive material at least at a surface thereof. The geometry of the structure supports propagation of surface plasmon polaritons at a selected frequency that is approximately equal to the resonant frequency of the material system. As a result, heavy electrons are produced at the electrically-conductive material as the surface plasmon polaritons propagate along the structure. Inventors: Zawodny; Joseph M.; (Poquoson, VA) Assignee: USA as represented by the Administrator of the National Aeronautics and Space Administration Washington DC Family ID: 44788191 Serial No.: 070552 Series 13 Code: Filed: March 24, 2011 Current U.S. Class: 376/108 Class at Publication: 376/108 Current CPC Class: G21B 3/00 20130101; Y02E 30/18 20130101 International Class: G21B 1/00 20060101 G21B001/00 Goverment Interests STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] The invention was made by an employee of the United States Government and may be manufactured and used by or for the Government of the United States of
    [Show full text]
  • Structural Chemistry and Metamagnetism of an Homologous Series of Layered Manganese Oxysulfides Zolta´Na.Ga´L,† Oliver J
    Published on Web 06/10/2006 Structural Chemistry and Metamagnetism of an Homologous Series of Layered Manganese Oxysulfides Zolta´nA.Ga´l,† Oliver J. Rutt,† Catherine F. Smura,† Timothy P. Overton,† Nicolas Barrier,† Simon J. Clarke,*,† and Joke Hadermann‡ Contribution from the Department of Chemistry, UniVersity of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, U.K., and Electron Microscopy for Materials Science (EMAT), UniVersity of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium Received February 7, 2006; E-mail: [email protected] Abstract: An homologous series of layered oxysulfides Sr2MnO2Cu2m-δSm+1 with metamagnetic properties is described. Sr2MnO2Cu2-δS2 (m ) 1), Sr2MnO2Cu4-δS3 (m ) 2) and Sr2MnO2Cu6-δS4 (m ) 3), consist of 2+ MnO2 sheets separated from antifluorite-type copper sulfide layers of variable thickness by Sr ions. All three compounds show substantial and similar copper deficiencies (δ ≈ 0.5) in the copper sulfide layers, and single-crystal X-ray and powder neutron diffraction measurements show that the copper ions in the m ) 2 and m ) 3 compounds are crystallographically disordered, consistent with the possibility of high two-dimensional copper ion mobility. Magnetic susceptibility measurements show high-temperature Curie- Weiss behavior with magnetic moments consistent with high spin manganese ions which have been oxidized to the (2+δ)+ state in order to maintain a full Cu-3d/S-3p valence band, and the compounds are correspondingly p-type semiconductors with resistivities around 25 Ω cm at 295 K. Positive Weiss temperatures indicate net ferromagnetic interactions between moments. Accordingly, magnetic susceptibility measurements and low-temperature powder neutron diffraction measurements show that the moments within a MnO2 sheet couple ferromagnetically and that weaker antiferromagnetic coupling between sheets leads to A-type antiferromagnets in zero applied magnetic field.
    [Show full text]
  • Low-Field-Enhanced Unusual Hysteresis Produced By
    PHYSICAL REVIEW B 94, 184427 (2016) Low-field-enhanced unusual hysteresis produced by metamagnetism of the MnP clusters in the insulating CdGeP2 matrix under pressure T. R. Arslanov,1,* R. K. Arslanov,1 L. Kilanski,2 T. Chatterji,3 I. V. Fedorchenko,4,5 R. M. Emirov,6 and A. I. Ril5 1Amirkhanov Institute of Physics, Daghestan Scientific Center, Russian Academy of Sciences (RAS), 367003 Makhachkala, Russia 2Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland 3Institute Laue-Langevin, Boˆıte Postale 156, 38042 Grenoble Cedex 9, France 4Kurnakov Institute of General and Inorganic Chemistry, RAS, 119991 Moscow, Russia 5National University of Science and Technology MISiS, 119049, Moscow, Russia 6Daghestan State University, Faculty of Physics, 367025 Makhachkala, Russia (Received 11 April 2016; revised manuscript received 28 October 2016; published 22 November 2016) Hydrostatic pressure studies of the isothermal magnetization and volume changes up to 7 GPa of magnetic composite containing MnP clusters in an insulating CdGeP2 matrix are presented. Instead of alleged superparamagnetic behavior, a pressure-induced magnetization process was found at zero magnetic field, showing gradual enhancement in a low-field regime up to H 5 kOe. The simultaneous application of pressure and magnetic field reconfigures the MnP clusters with antiferromagnetic alignment, followed by onset of a field-induced metamagnetic transition. An unusual hysteresis in magnetization after pressure cycling is observed, which is also enhanced by application of the magnetic field, and indicates reversible metamagnetism of MnP clusters. We relate these effects to the major contribution of structural changes in the composite, where limited volume reduction by 1.8% is observed at P ∼ 5.2 GPa.
    [Show full text]
  • Metamagnetism in Linear Chain Electron-Transfer Salts Based on Decamethylferrocenium and Metal–Bis(Dichalcogenate) Acceptors
    www.elsevier.com/locate/ica Inorganica Chimica Acta 326 (2001) 89–100 Metamagnetism in linear chain electron-transfer salts based on decamethylferrocenium and metal–bis(dichalcogenate) acceptors S. Rabac¸a a, R. Meira a, L.C.J. Pereira a, M. Teresa Duarte b, J.J. Novoa c, V. Gama a,* a Departamento Quı´mica, Instituto Tecnolo´gico e Nuclear, P-2686-953 Saca6e´m, Portugal b Departamento Engenharia Quı´mica, Instituto Superior Te´cnico, P-1049-001 Lisbon, Portugal c Departamento Quı´mica Fı´sica and CER Quimica Teo´rica, Uni6ersidad de Barcelona, A6. Diagonal 647, 08028 Barcelona, Spain Received 15 May 2001; accepted 12 September 2001 In memory of Professor Olivier Kahn Abstract The crystal structure of the electron-transfer (ET) salts [Fe(Cp*)2][M(tds)2], with M=Ni (1) and Pt (2), consists of an array of + − \ parallel alternating donors, [Fe(Cp*)2] , and acceptors, [M(tds)2] , ···DADADA···, stacks. For T 20 K, the magnetic susceptibility follows a Curie–Weiss behavior, with q values of 8.9 and 9.3 K for 1 and 2, respectively. A metamagnetic behavior was observed in 2, with TN =3.3 K and HC =3.95 kG at 1.7 K, resulting from a high magnetic anisotropy. A systematic study of the intra and interchain magnetic interactions was performed on 1, 2 and other ET salts based on decamethylferrocenium and on metal–bis(dichalcogenate) acceptors, with a similar crystal structure. The observed magnetic behavior of these compounds is consistent with the presence of strong ferromagnetic intrachain DA interactions and weaker antiferromagnetic interchain interactions, predicted by the McConnell I model.
    [Show full text]
  • Table of Contents (Online, Part 1)
    PERIODICALS PHYSICAL REVIEW BTM Postmaster send address changes to: For editorial and subscription correspondence, APS Subscription Services please see inside front cover Suite 1NO1 (ISSN: 1098-0121) 2 Huntington Quadrangle Melville, NY 11747-4502 THIRD SERIES, VOLUME 83, NUMBER 4 CONTENTS JANUARY 2011-15(II) RAPID COMMUNICATIONS Electronic structure and strongly correlated systems Signatures of Wigner localization in epitaxially grown nanowires (4 pages) ................................. 041101(R) L. H. Kristinsdottir,´ J. C. Cremon, H. A. Nilsson, H. Q. Xu, L. Samuelson, H. Linke, A. Wacker, and S. M. Reimann Suppression of metal-insulator transition at high pressure and pressure-induced magnetic ordering in pyrochlore oxide Nd2Ir2O7 (4 pages) ............................................................................ 041102(R) Masafumi Sakata, Tomoko Kagayama, Katsuya Shimizu, Kazuyuki Matsuhira, Seishi Takagi, Makoto Wakeshima, and Yukio Hinatsu LDA + DMFT study of Ru-based perovskite SrRuO3 and CaRuO3 (4 pages) ................................ 041103(R) E. Jakobi, S. Kanungo, S. Sarkar, S. Schmitt, and T. Saha-Dasgupta √ √ Geometrical frustration and the competing phases of the Sn/Si(111) 3 × 3R30◦ surface systems (4 pages) . 041104(R) Gang Li, Manuel Laubach, Andrzej Fleszar, and Werner Hanke Relativistic effects in a phosphorescent Ir(III) complex (4 pages) .......................................... 041105(R) A. R. G. Smith, M. J. Riley, S.-C. Lo, P. L. Burn, I. R. Gentle, and B. J. Powell Impurity scattering in a Luttinger liquid with electron-phonon coupling (4 pages) ............................ 041106(R) Alexey Galda, Igor V. Yurkevich, and Igor V. Lerner Semiconductors I: bulk Persistent polarization memory in sexithiophene nanostructures (4 pages) ................................... 041201(R) Benoit Gosselin, Vincent Cardin, Alexandre Favron, Jelissa De Jonghe, Laura-Isabelle Dion-Bertrand, Carlos Silva, and Richard Leonelli Candidates for topological insulators: Pb-based chalcogenide series (4 pages) ..............................
    [Show full text]
  • Spin Canting, Metamagnetism, and Single-Chain Magnetic Behaviour in the Cyano-Bridged Homospin Iron(II) Compound
    Electronic Supplementary Material (ESI) for ChemComm. This journal is © The Royal Society of Chemistry 2015 Electronic Supplementary Material (ESI) for Chem. Commun. This journal is © The Royal Society of Chemistry 2014 Spin canting, metamagnetism, and single-chain magnetic behaviour in the cyano-bridged homospin Iron(II) compound Dong Shao, Shao-Liang Zhang, Xin-hua Zhao, Xin-Yi Wang* † State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China. *Email: [email protected] Supporting Information 1 Table of contents: 1. Physical Measurements……………………………………………………………..3 2. Synthesis…………………………………………………………………………….3 3. X-ray crystallography……………………………………………………………….4 3.1 X-ray data collection, structure solution and refinement for 1 ……………………………4 Table S1 Crystallographic Data and Structure Refinement Parameters for 1 …………………5 Table S2 Selected Bond Lengths (Ǻ) and Bond Angles (deg) in 1 ……………………………6 Figure S1 The asymmetric unit of 1…………………………………………….……….……6 Figure S2 The packing diagram of 1 showing the interchain distances.………………………6 4. Magnetic Properties…………………………………………………………………………….7 Figure S3 Field-dependent isothermal magnetization curve for 1 below 7 K.…...……………7 Figure S4 The derivatives of the magnetization (dM /dH vs H) of 1 ……………….…………7 Figure S5 A series of magnetic susceptibility curves of 1 measured at different dc fields.…...8 Figure S6 Frequency dependence of χ' and χ" of the ac susceptibility for 1 at different temperatures at 0 or 2200 Oe dc fields.
    [Show full text]
  • Anomalous Metamagnetism in the Low Carrier Density Kondo Lattice Ybrh3si7
    PHYSICAL REVIEW X 8, 041047 (2018) Anomalous Metamagnetism in the Low Carrier Density Kondo Lattice YbRh3Si7 Binod K. Rai,1 S. Chikara,2 Xiaxin Ding,2 Iain W. H. Oswald,3 R. Schönemann,4 V. Loganathan,1 A. M. Hallas,1 H. B. Cao,5 Macy Stavinoha,6 T. Chen,1 Haoran Man,1 Scott Carr,1 John Singleton,2 Vivien Zapf,2 Katherine A. Benavides,3 Julia Y. Chan,3 Q. R. Zhang,4 D. Rhodes,4 Y. C. Chiu,4 Luis Balicas,4 A. A. Aczel,5 Q. Huang,7 Jeffrey W. Lynn,7 J. Gaudet,8 D. A. Sokolov,9 H. C. Walker,10 D. T. Adroja,10 Pengcheng Dai,1 Andriy H. Nevidomskyy,1 C.-L. Huang,1,* and E. Morosan1 1Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA 2National High Magnetic Field Laboratory, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA 3Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, USA 4National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA 5Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA 6Department of Chemistry, Rice University, Houston, Texas 77005, USA 7NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA 8Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada 9Max Planck Institute for Chemical Physics of Solids, Dresden, 01187 Germany 10ISIS Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, United Kingdom (Received 10 March 2018; revised manuscript received 26 September 2018; published 13 December 2018) We report complex metamagnetic transitions in single crystals of the new low carrier Kondo anti- ferromagnet YbRh3Si7.
    [Show full text]
  • Chapter One Introduction
    Chapter One Introduction 1.1 Prelude All materials exhibit magnetism, but magnetic behavior depends on the electron configuration of the atoms and the temperature. The electron configuration can cause magnetic moments to cancel each other out (making the material less magnetic) or align (making it more magnetic). Increasing temperature increases random thermal motion, making it harder for electrons to align, and typically decreasing the strength of a magnet. Magnetism may be classified according to its cause and behavior. The main types of magnetism are (chiba et al., 2005): Diamagnetism: All materials display diamagnetism, which is the tendency to be repelled by a magnetic field. However, other types of magnetism can be stronger than diamagnetism, so it is only observed in materials that contain no unpaired electrons. When electrons pairs are present, their "spin" magnetic moments cancel each other out. In a magnetic field, diamagnetic materials are weakly magnetized in the opposite direction of the applied field. Examples of diamagnetic materials include gold, quartz, water, copper, and air. Paramagnetism: In a paramagnetic material, there are unpaired electrons. The unpaired electrons are free to align their magnetic moments. In a magnetic field, the magnetic moments align and are magnetized in the direction of the applied field, reinforcing it. Examples of paramagnetic materials include magnesium, molybdenum, lithium, and tantalum. Ferromagnetism: Ferromagnetic materials can form permanent magnets and are attracted to magnets. Ferromagnets have unpaired electrons, plus 1 the magnetic moment of the electrons tends to remain aligned even when removed from a magnetic field. Examples of ferromagnetic materials include iron, cobalt, nickel, alloys of these metals, some rare earth alloys, and some manganese alloys.
    [Show full text]
  • Magnetic Transitions Under High Magnetic Fields
    1 Magnetic transitions under high magnetic fields V. Simonet Institut Néel, CNRS/UJF, Grenoble, France X-ray Spectroscopy in High Magnetic Field, SOLEIL 2010 17/11/10 2 Outline of the lecture Introduction: effect of external magnetic field Magnetization processes and frustration Metamagnetism in metals Competing degrees of freedom Level crossing Quantum magnetism Conclusion X-ray Spectroscopy in High Magnetic Field, SOLEIL 2010 17/11/10 3 Outline of the lecture Introduction: effect of external magnetic field Magnetization processes and frustration Metamagnetism in metals Competing degrees of freedom Level crossing Quantum magnetism Conclusion X-ray Spectroscopy in High Magnetic Field, SOLEIL 2010 17/11/10 4 Introduction: effect of external magnetic field Zeeman term: competition with other terms in energy Metamagnetism: phase transition (1st or 2nd order) towards new magnetic state (≠ moments orientation and/or magnitude) Most often AFM towards FM 1st order 2nd order Magnetization plateaus: constant magnetization M at M=0 or at finite M before saturation X-ray Spectroscopy in High Magnetic Field, SOLEIL 2010 17/11/10 5 Introduction: effect of external magnetic field Zeeman term: competition with: Exchange interactions molecular field up to 1000 T and magnetocrystalline anisotropy 100s of T : high fields needed quantitative information on interactions, energy levels, etc… + new model systems Tools : NMR, neutron scattering, magnetic susceptibility, magnetization, Torque, specific heat, IR/optical spectroscopy, ESR, ultra-sound… and of
    [Show full text]
  • Metamagnetism of Weakly-Coupled Antiferromagnetic Topological
    Metamagnetism of weakly-coupled antiferromagnetic topological insulators Aoyu Tan, Valentin Labracherie, Narayan Kunchur, Anja Wolter, Joaquin Cornejo, Joseph Dufouleur, Bernd Büchner, Anna Isaeva, Romain Giraud To cite this version: Aoyu Tan, Valentin Labracherie, Narayan Kunchur, Anja Wolter, Joaquin Cornejo, et al.. Metamag- netism of weakly-coupled antiferromagnetic topological insulators. Physical Review Letters, American Physical Society, 2020, 124 (197201). hal-02457539 HAL Id: hal-02457539 https://hal.archives-ouvertes.fr/hal-02457539 Submitted on 28 Jan 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Metamagnetism of weakly-coupled antiferromagnetic topological insulators Aoyu Tan1,2, Valentin Labracherie1,2, Narayan Kunchur2, Anja U.B. Wolter2, Joaquin Cornejo2, Joseph Dufouleur2,3, Bernd B¨uchner2,4, Anna Isaeva2,4, and Romain Giraud1,2 1Univ. Grenoble Alpes, CNRS, CEA, Spintec, F-38000 Grenoble, France 2Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany 3Center for Transport and Devices, TU Dresden, D-01069 Dresden, Germany 4Faculty of Physics, TU Dresden, D-01062 Dresden, Germany (Dated: 9th January 2020) Abstract The magnetic properties of the van der Waals magnetic topological insulators MnBi2Te4 and MnBi4Te7 are investigated by magneto-transport measurements.
    [Show full text]
  • Yttrium Barium Copper Oxide 15 Liquid Nitrogen 20
    Wiki Book Mounir Gmati Wiki Book Mounir Gmati Lévitation Quantique: Les ingrédients et la recette PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Mon, 14 Nov 2011 01:54:04 UTC Wiki Book Mounir Gmati Contents Articles Superconductivity 1 Superconductivity 1 Type-I superconductor 14 Yttrium barium copper oxide 15 Liquid nitrogen 20 Magnetism 23 Magnetism 23 Magnetic field 33 Flux pinning 54 Magnetic levitation 55 References Article Sources and Contributors 63 Image Sources, Licenses and Contributors 65 Article Licenses License 66 Wiki Book Mounir Gmati 1 Superconductivity Superconductivity Superconductivity is a phenomenon of exactly zero electrical resistance occurring in certain materials below a characteristic temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the A magnet levitating above a high-temperature idealization of perfect conductivity in classical physics. superconductor, cooled with liquid nitrogen. Persistent electric current flows on the surface of The electrical resistivity of a metallic conductor decreases gradually as the superconductor, acting to exclude the temperature is lowered. In ordinary conductors, such as copper or magnetic field of the magnet (Faraday's law of silver, this decrease is limited by impurities and other defects. Even induction). This current effectively forms an electromagnet that repels the magnet.
    [Show full text]
  • Springer Theses
    Springer Theses Recognizing Outstanding Ph.D. Research Aims and Scope The series “Springer Theses” brings together a selection of the very best Ph.D. theses from around the world and across the physical sciences. Nominated and endorsed by two recognized specialists, each published volume has been selected for its scientific excellence and the high impact of its contents for the pertinent field of research. For greater accessibility to non-specialists, the published versions include an extended introduction, as well as a foreword by the student’s supervisor explaining the special relevance of the work for the field. As a whole, the series will provide a valuable resource both for newcomers to the research fields described, and for other scientists seeking detailed background information on special questions. Finally, it provides an accredited documentation of the valuable contributions made by today’s younger generation of scientists. Theses are accepted into the series by invited nomination only and must fulfill all of the following criteria • They must be written in good English. • The topic should fall within the confines of Chemistry, Physics, Earth Sciences, Engineering and related interdisciplinary fields such as Materials, Nanoscience, Chemical Engineering, Complex Systems and Biophysics. • The work reported in the thesis must represent a significant scientific advance. • If the thesis includes previously published material, permission to reproduce this must be gained from the respective copyright holder. • They must have been examined and passed during the 12 months prior to nomination. • Each thesis should include a foreword by the supervisor outlining the significance of its content. • The theses should have a clearly defined structure including an introduction accessible to scientists not expert in that particular field.
    [Show full text]