In everyday life, phase transitions - like when water boils and turns into steam or freezes and becomes ice - are caused by changes in temperature. Here, very high magnetic fields are used to reveal a quantum phase transition not caused by temperature, but instead driven by quantum mechanics upon changing the concentration of electrons, work that could hold critical clues that explain high-temperature superconductivity.
Researchers studied the mechanics of supercurrent flow in state-of-the-art Bi-2212 superconducting round wires and learned that the microstructure of the superconducting filaments is inherently resilient, work that could open the door to new opportunities to raise supercurrent capacity of Bi-2212 round wires.
Electrons in metals behave like chaotic bumper cars, crashing into each other at every opportunity. While they may be reckless drivers, this result demonstrates that this chaos has a limit established by the laws of quantum mechanics. Using the 45T hybrid magnet and a crystal of high-temperature superconducting material, scientists were able to measure this boundary using high fields to bend electron trajectories to their will.
Researchers working to push the high temperature superconducting material (Bi-2212) to the forefront of superconducting magnet technology have used novel characterization methods to understand the complex relationship between its processing and its superconducting properties, specifically its current carrying capabilities.
A new device enables the testing of superconducting cables to high current without the high helium consumption associated with traditional current leads. This superconducting transformer will play an important role in testing cables needed for next-generation superconducting magnets.
The MagLab's 32 T all-superconducting magnet is now serving users at full field. An early experiment in the magnet identified an important milestone on the road to quantum computers.
This highlight focuses on the development of new thermometry required to study quantum materials and phenomena in high magnetic fields and at ultralow temperatures. The team has demonstrated that exceedingly small quartz tuning forks bathed in liquid 3He maintain a constant calibration that is magnetic field independent, thereby opening the use of these devices as new sensors of the response of quantum systems.
Physics does not yet know why copper-based superconductors (cuprates) conduct electrical current without dissipation at unprecedentedly high temperatures. Ultra high magnetic fields are used here to suppress superconductivity in a cuprate near absolute zero temperature, revealing an underlying transition to an electronic phase that might be the cause of the superconductivity.
A recent test coil with more than 1300 meters of conductor successfully demonstrated a new winding technique for insulated REBCO technology and was fatigue cycled to high strain for hundreds of cycles. This is the MagLab's first "two-in-hand" wound coil and the first fatigue cycling test of a coil of this size, both of which are very important milestones on the path to a 40T user magnet.
This research clarifies fundamental relationships between magnetism, superconductivity and the nature of the enigmatic “pseudogap state" in cuprate superconductors. The discovery provides an additional puzzle piece in the theoretical understanding of high-temperature superconductors - a key towards improving and utilizing these materials for technological applications.