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.
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.
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.
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.
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.
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.
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.