Graphene, a single two-dimensional sheet of carbon atoms with an arrangement mimicking the honeycomb hexagonal architecture, has captured immense interest of the scientific community since its isolation in 2004. Besides its extraordinarily high electrical conductivity and surface area, graphene shows a long spin lifetime and limited hyperfine interactions, which favors its potential exploitation in spintronic and biomedical applications, provided it can be made magnetic. However, pristine graphene is diamagnetic in nature due to solely sp2 hybridization. Thus, various attempts have been proposed to imprint magnetic features into graphene. The present review focuses on a systematic classification and physicochemical description of approaches leading to equip graphene with magnetic properties. These include introduction of point and line defects into graphene lattices, spatial confinement and edge engineering, doping of graphene lattice with foreign atoms, and sp3 functionalization. Each magnetism-imprinting strategy is discussed in detail including identification of roles of various internal and external parameters in the induced magnetic regimes, with assessment of their robustness. Moreover, emergence of magnetism in graphene analogues and related 2D materials such as transition metal dichalcogenides, metal halides, metal dinitrides, MXenes, hexagonal boron nitride, and other organic compounds is also reviewed. Since the magnetic features of graphene can be readily masked by the presence of magnetic residues from synthesis itself or sample handling, the issue of magnetic impurities and correct data interpretations is also addressed. Finally, current problems and challenges in magnetism of graphene and related 2D materials and future potential applications are also highlighted.

Emerging chemical strategies for imprinting magnetism in graphene and related 2D materials for spintronic and biomedical applications

Structure and strength of hydrogen bonds in inorganic solids

Japan. Ministry of Education, Culture, Sports, Science and Technology (MEXT) (Grant No. 20001006)

Observation of magnetic edge state in graphene nanoribbons

Hydration of Ions.- Interactions of Water in Ionic Hydrates.- The Determination of Vibrational Frequencies in H-Bonded Liquids from Molecular Dynamics Simulations.- A Model of Ion Hydration.- Infrared Spectroscopic Study on Anion-Hydration in CH2-Cl2.- Infrared Spectroscopic Study of the Strengthening of H-bonds in Aqueous Salt Solutions.- Infrared Studies of Ionic Hydration in Aqueous Solutions.- Interactions of Cations of the Mn(II) - Zn(II) Series with Water in Solutions: Isopiestic and Spectral Results.- Raman Spectroscopic Investigations Concerning the Solvation Behaviour of Aluminium Chloride in Mixed Solvents.- Dissociation Field Effect of MgSO4 Ion-Pair Hydrates.- Hydrogen Bonding and Dehydration in Selenate Hydrates.- Water Molecules in Solid Hydrates - Correlation of Spectroscopic and Crystallographic Data.- Stretching Frequency Versus Bond Distance Correlation of H-Bonds in Crystalline Hydrates: The Role of the Proton Acceptors.- Uncoupled HDO Modes Caused by Metal Guest Ions in Crystal Matrices.- Water in the Hydro-Sodalite System Na6+x, (AlSiO 4)6(OH)x *nH2O with 0? x? 2 and 0? n? 8.- On the Interpretation of Isotope Effect in Mossbauer Spectroscopy.- Isotope Effects on Nuclear Shielding as a Means of Studying Solute-Solvent Interactions.- Molecular Reorientations and Local Structure in Nitrate Aqueous Solutions.- Hydration of Nonionic Substances.- Similarities and Differences in Ionic and Nonionic Hydrates.- Mixed Hydrogen Bond Chains.- Dilute Aqueous Solutions of Nonelectrolytes: Recent Advances.- Thermodynamics of DMSO Hydration.- NMR Relaxation in Clathrate-Hydrates.- NMR of Inert Gases in Aqueous Solutions.- Fluctuations of Thermodynamic Properties of Supercooled Liquid Water.- Ab Initio Calculations and Many Body Analysis of the Water Tetramer.- Hydration of Biological Macromolecular Substances.- Solvent Effects on the Structural Stability and Interactions of Globular Proteins: The Role of Cooperativity and Repulsive Restraints.- Exchange of the Structural Water and Molecular Dynamic in Collagen.- Hydration Effects on Photosynthetic Membranes and Proteins.- Photosynthesis: Dynamics of Proteins and Charge Transfer.- Infrared Spectroscopy of Hydration Effects in Photosynthetic Reaction Centers.- Intramolecular Protontransfers in Bacteriorhodopsin Monitored by Fourier Transform Infrared Difference Spectroscopy.- Hydration of Chlorophyll a.- The Reaction of NO and SO2 in the Presence of Water as a Possible Reason for the Destruction of Chlorophyll in the Wetterstein-Mountains (Bavaria).- A Simple Microwave Argument about the Changes of Structure of Water in Solutions of Macromolecules.- IR-Spectroscopic Studies on the Hydration of Polyglycolethers.- The Role of Ion Hydration in the Biological Effect of Alkali Cations.- Water Permeation Measured by Solvent Isotope Effects.- The Physical State and Energization of Biological Membranes Regulate Permeation of Water, Electrolytes and Non-Electrolytes.- Structure and Dynamics of one Dimensional Ionic Solutions in Narrow Transmembrane Channels - A Molecular Dynamics Simulation Study.- Computer Simulations of Water Interactions Near Single Crystal Surfaces.- Hydrogen Bond Connectivity of Water in Hydrophilic Confinements.- Water and Surfactants.- Water and Solvents on Surfaces Bristling with Alkyl Chains.- Hydrophile-Lipophile-Balance and Interfacial Tensions in Water-Hydrocarbon-Surfactant Systems.- Raman Spectroscopic Analysis of Surfactants in the Neat, Monomeric and Micellar Phases.- Effect of Temperature and Aprotic Solvents on the CMC of Sodium Dodecyl Sulphate.- Methods, Models and Theories.- Matrix Isolation Spectroscopy of Low Stoichiometry Complexes between Water and Sulfur Dioxide.- Infrared Photodissociation of the H2O:HI Complex Trapped in Solid Nitrogen. Comparison with the CH3CN:HI Complex.- Neutron Scattering and Infrared Spectroscopy of H2O Molecules Isolated in Diverse Cryogenic Matrices.- Ab Initio Studies of Complexes Formed by HF and HCL with H2O.- Frequency Shifts of Carbonyl Streching Bands Induced by Solvents.- Accessibility of the Lone Pair and Hydrogen Bonding Site in Biological Systems.- Infrared Spectroscopy - A Reliable Source of Information on Hydrogen Bonding?.- On a "Critical" Behaviour of Strong Hydrogen Bonds.- Does an OH or an OD Group Form the Strongest Hydrogen Bond to Oxygen?.- Phase Transition in Solid 2,3,3-Trimethylbutan-2-ol Hemihydrate (TMBH).- The Influence of the Structure of Water on Chemical Reactions.- Cartesian-Spherical Transformation Formalism and the Theoretical Insight into Many-Body Long-Range Forces of the Electrostatic Origin in Multimolecular Systems.- Authors Index.

Interactions of Water in Ionic and Nonionic Hydrates: Proceedings of a Symposium in honour of the 65th birthday of W.A.P. Luck Marburg/FRG, 2.-3.4. 1987

The direct observation of real time electrochemical processes is of great importance for fundamental research on battery materials. Here, we use electron paramagnetic resonance (EPR) spectroscopy to monitor the electrochemical reaction of sodium ions with few-layer MoS2 and its composite with carbon nanotubes (CNTs), thereby uncovering new details of the reaction mechanism. We propose that the sodiation reaction takes place initially in structural defects at the MoS2 surface that have been created during the synthetic process (ultrasonic exfoliation), leading to a decrease in the density of Mo5+ at low symmetry sites that can be related to the electrochemical irreversibility of the process. In the case of the few-layer MoS2/CNTs composite, we found metallic-type conduction behavior for the electrons associated with the Mo paramagnetic centers and improved electrochemical reversibility. The reversible nature of the EPR spectra implies that adsorption/desorption of Na+ ions occurs on the Mo5+ defects, or th...

Electrochemical Interaction of Few-Layer Molybdenum Disulfide Composites vs Sodium: New Insights on the Reaction Mechanism

ESR study of spin relaxation in graphene

We report electron paramagnetic resonance (EPR) evidence of the antiferromagnetic ordering in pristine single-layer graphene. Temperature dependences of the parameters of EPR spectra obtained for vacuum-processed samples were studied within the temperature range of 4.2–300 K. Our experiment has confirmed recent theoretical predictions that in single-layer graphene the carrier-mediated exchange interaction leads to antiferromagnetic coupling. We note some quantitative discrepancies between the theory and experimental findings and discuss their origins. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

/pdf/epr-evidence-of-antiferromagnetic-ordering-in-single-layer-f47whfogz9.pdf

EPR evidence of antiferromagnetic ordering in single-layer graphene

Discussion of the origin of paramagnetic centres observed by electron paramagnetic resonance in graphene oxide (GO) and reduced graphene oxide (rGO) is done on the assumption that GO can be considered as a functionalized graphene. This leads to the conclusion that the narrow signal with g close to 2, observed for GO and thermally reduced GO, is due to paramagnetic centres localized on defects and exchange coupled to conduction electrons. Randomness of graphene modi cation results in variety of parameters of EPR signals. The broad signals observed in GO and rGO and ascribed to magnetic clusters on the zig-zag edge states indicate that the edge magnetism can be preserved by functionalization.

/pdf/magnetic-centres-in-functionalized-graphene-1dung5phek.pdf

Magnetic Centres in Functionalized Graphene

We studied magnetic properties of a composite of para n and graphene akes Magnetic properties of this composite were investigated by ferromagnetic resonance/electron spin resonance technique The ferromagnetic resonance signal from graphene suspension in para n is broad and shifted from magnetic eld corresponding to g ≈ 2 to the low magnetic eld The temperature dependence of the spectra shows that magnetic ordering in the studied system is sensitive to thermal uctuations These features are expected for the 1D ferromagnetism and the obtained results are analyzed in the frame of the theoretical predictions concerning magnetic correlations at graphene edges Therefore, based on our investigation we can conclude the existence of the magnetic edges in graphene and presence of the ferromagnetic correlations between edge spins

http://przyrbwn.icm.edu.pl/APP/PDF/127/a127z2p123.pdf

Mariusz Maćkowiak

Papers

ESR study of spin relaxation in graphene

EPR evidence of antiferromagnetic ordering in single-layer graphene

Magnetic Centres in Functionalized Graphene

FMR Evidence of Stable Ferromagnetic Correlations at Zigzag Edge States in Graphene

FMR evidence of ferromagnetic correlations at zigzag edge states in single-layer graphene