Research on La2-xSrxCuO4 provides a new perspective on the mechanism for the superconductor-insulator transition in cuprates, one of the key questions in condensed matter physics.

Josephson vortices were unexpectedly observed in the high-temperature iron superconductor SmFeAs(O,F), despite the material’s low electronic anisotropy. This development is important for the future deployment in high-Tc cable technology.

Here we study the microstructural and transport properties of Co-Ba122 thin films in which secondary non-superconducting phases have been introduced during film growth in two different ways: first by using a Co-Ba122 target with a small amount of oxygen, second by alternating two different targets: a clean CoBa122 and an undoped Ba122 target.

A prototype high-temperature superconducting coil for the 32 T all-superconducting magnet was constructed with YBCO tape and successfully tested in the large-bore resistive magnet at the MagLab.

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.

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

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.

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).

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.

How researchers use powerful magnets to learn about materials.

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