Science Highlights

These monthly highlights, selected by MagLab Director Greg Boebinger, represent the most promising and cutting-edge research underway in the lab’s seven user facilities.

15 April 2013

High-Frequency and -Field EPR Detection of a Di-radical Intermediate

This work defines a new mechanism for radical-mediated catalysis of a protein substrate, and has broad implications for applied biocatalysis and for understanding oxidative protein modification during oxidative stress.

15 February 2013

Characterization of Pine Pellet and Peanut Hull Pyrolysis Bio-Oils by Negative-Ion Electrospray Ionization FT&-ICR Mass Spectrometry

Pyrolysis of solid biomass, in this case pine pellets and peanut hulls, generates a hydrocarbon-rich liquid product (bio-oil) consisting of oily and aqueous phases. Here, each phase is characterized by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to yield unique chemical formulas for thousands of compounds.

15 February 2013

Magnetic Structure and Magneto–electric Coupling in Multiferroics

Multiferroics — “Spintronics without heat” — coupled ferromagnetism and ferroelectricity can provide a new class of functional materials for needed applications including magnetic sensing, data storage and manipulation, high–frequency and high–power electronics, and energy savings.

15 January 2013

Quantum Oscillations in a Candidate Topological Superconductor, a Copper-doped Topological Insulator: Cu1/4Bi2Se3

A superconducting ground state has been observed at T < 3.8 K in copper-doped Bi2Se3 single crystals. Topological superconductivity is predicted in this material, assuming the superconducting electrons follow the linear energy-momentum dispersion (Dirac-like) seen in graphene and other materials of current interest. However, this presumption had not yet been confirmed by quantum oscillation measurements.

15 January 2013

Male and Female Mating Pheromones in Panagrellus redivivus

Nematodes are the most abundant animal on earth, and they live in virtually every ecological niche on earth. Parasitic species have a significant health and economic impact through the infection of crops, domestic animals, and humans. Therefore, we are working to unravel the chemical language used by nematodes, with the ultimate goals of better understanding the role of small molecules in regulating behavior and of developing new approaches to control nematode parasites.

15 December 2012

Di-Nitrogen Activation by Vanadium(III) Complexes for Chemical Catalysis

Researchers from the National High Magnetic Field Laboratory user program performed high-frequency (329 GHz) electron magnetic resonance (EMR) experiments to address questions of fundamental importance in catalysis 1) improving industrial production of ammonia and ammonia-derived fertilizers, and 2) understanding of the atmospheric nitrogen cycle.

15 December 2012

Large Cable-in-Conduit Coil Fabrication at the MagLab

MagLab engineers are building two cable-in-conduit superconducting coils for hybrid magnets, each with a resistive inner coil and a superconducting outer coil.

15 December 2012

Filament Fracture in ITER Conductor under Cyclic Lorentz Force Loading

First direct evidence that filament fracture accompanies degradation of superconducting cables designed for the International Thermonuclear Experimental Reactor (ITER). The tokomak fusion reactor, now under construction in France, is an international collaboration crucial to future energy generation from nuclear fusion.

15 November 2012

Relativistic Fermions and Quantum Magnetoresistance in CaMnBi2

We report two-dimensional (2D) Dirac fermions and quantum magnetoresistance (MR) in Bi square nets of CaMnBi2 crystals.

15 November 2012

High-Resolution MRI Probe for STRAFI Studies of Solid Material

Magnetic resonance imaging (MRI) of solid materials entails numerous problems from short longitudinal relaxation (T2) times to requiring strong gradients to attain high resolution images. A promising technique to address these issues is the Stray Field Imaging (STRAFI) method.

15 October 2012

Powerful New Ionization Technique for Mass Spectroscopy That Avoids Fragmentation of Saturated Hydrocarbons

Here, we present a powerful new approach for the analysis of saturated hydrocarbon mixtures: atmospheric pressure laser- induced acoustic desorption chemical ionization (AP/LIAD-CI) with oxygen carrier/reagent gas.

15 September 2012

Symmetry Breaking in Graphene

Tilted magnetic fields were used to classify the broken symmetry states by their spin polarization. It was found that graphene turns into either a spin ferromagnet or some variety of density wave.

15 August 2012

Understanding Nanoscale Magnetization Dynamics via High-Field EPR

Molecules that exhibit slow magnetic relaxation upon removal from a polarizing magnetic field are referred to as single-molecule magnets (SMMs). SMMs receive considerable attention owing to their potential utility in applications such as spin-based information storage. In these systems, the slow relaxation normally arises from the action of an easy-axis magnetic anisotropy, quantified by a negative axial zero-field splitting parameter, D < 0, on a high-spin ground state. Two separate EPR studies carried out in the DC field facility by users from UC Berkeley (chemistry) have identified compounds that undergo slow relaxation, even though the relevant magnetic ions possess easy-plane-type anisotropy (i.e. D > 0).

15 August 2012

High Critical Current Density in Fine-grain (Ba0.6K0.4)Fe2As2

Ferro-pnictide superconductors attracted immediate attention for potential applications due to their high superconducting transition temperatures (Tc up to 56 K) and high upper critical magnetic fields (Hc2 over 100 T). Unfortunately, much as in cuprates, grain boundaries (GBs) were found to obstruct their current carrying capability. This posed a serious technological problem because wires for magnets cannot be single crystals and, thus, inevitably contain grain boundaries. This work shows that low-temperature synthesis of the compound (Ba0.6K0.4)Fe2As2 (Ba-122) in the form of polycrystalline wire achieves a current density three times that of state-of-the-art Nb3Sn wires.

16 July 2012

Novel Fractional Quantum Hall States in Two-Dimensional Electron Systems

This experiment probes the nature of the 12/5 Fractional Quantum Hall state by using a hydraulic-driven rotator to tilt the two-dimensional system in a magnetic field.

16 July 2012

Adjustable Sliding Ring Coil for Neuroimaging in Vertical High Fields

Biomedical researchers have a unique tool to investigate a variety of living and excised specimen with the MagLab’s 21.1 T 900-MHz ultra-widebore (105-mm) vertical magnet. However, there are challenges to performing research in a high-field vertical magnet, which have been addressed by a NHMFL-led team of international scientists working to make very high field or ultra high field MRI more flexible. This team has constructed a tunable sliding ring transmit/receive volume coil for 900-MHz hydrogen MRI that provides the uniformity and sensitivity for high resolution and functional imaging of living samples while accommodating unique excised samples to improve characterization and throughput. This new design incorporates the apparatus necessary for maintaining animals in a vertical position while providing remote tuning and sample flexibility beyond most available coils.

15 June 2012

The Smallest Stable Fullerene, M@C28 (M = Ti, Zr, U)

Buckminster Fullerenes ("Buckyballs") have fascinated chemists since the original discovery of C60, leading to the 1996 Nobel Prize in Chemistry for Curl, Kroto and Smalley. Although fullerenes of various sizes have since been observed, the theoretically smallest fullerene, C28, has until now escaped detection, due to its high curvature and thus high reactivity.

15 June 2012

Magnetostriction and Magnetic Texture to 100.75 Tesla in Frustrated SrCu2(BO3)2

Magnetic systems provide controllable “model” systems to study interacting many body quantum effects, relevant to poorly understood problems beyond the realm of magnetism. For example, disorder leads to Bose glass behavior, enabling study of the Bose-glass to BEC transition in quantum magnets — a key component to understanding the superconductor-to-insulator quantum phase transition. High magnetic fields drive Bose glasses into Bose-Einstein condensates.

15 May 2012

First Superfluorescence in a Solid

Superfluorescence, historically, is the spontaneous emission of light from a collection of excited atoms. Scientists visiting the MagLab recently discovered superfluorescence for the first time in a solid material, by shining an extremely brief pulse of light on a layered semiconductor located in an intense magnetic field. In response, superfluorescent light of a different color was emitted thirty trillionths of a second later. Superfluorescence can be used to produce light of any desired color and could be enhanced to occur at room temperature and without magnetic fields. Superfluorescent devices would be powerful tools for optical communications.

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