New kind of quantum Hall state observed in graphene superlattices.

This week at the lab, scientists in the DC Field Facility met to determine what experiments will take place in some of the world’s largest magnets next year.

Scientists from all over the world apply to use these magnets, which are available for free, and demand always exceeds supply. Most of the dozen high-field magnets housed there, including the world-record 45 tesla hybrid magnet, use a lot of electricity. This limits how many magnets the facility can operate at a time, which in turn limits the number of scientists who can do experiments there.

"We have a limited resource we need to distribute," DC Field Facility Director Tim Murphy told a group of fellow physicists charged with deciding which of the 47 experiment proposals to select for the 33 “magnet time” spaces available in the upcoming cycle.

The group gathers three times a year to assess and select proposals, judging them on several criteria. How feasible is the work? Did the scientist’s previous experiments at the MagLab result in interesting findings or publications? What did the external reviewers who graded the proposal think about the science?

Sometimes researchers who request a stronger magnet are assigned to another instrument so that they can first obtain results at a lower field. Other times, an exciting proposal that might not yield the hoped-for results gets the green light because it’s the type of high-risk, high-reward experiment that might just be the next big Nature paper.

"Sometimes you have to go for it," said MagLab physicist Stan Tozer.

Researchers who made the cut this week will be notified by mid-December (after staff complete the scheduling process) and conduct their experiments between January and May of next year.


Photo by Stephen Bilenky / Text by Kristen Coyne

Just as all matter may exist in the three famous everyday phases — solid, liquid and gas — complex materials may exist in a combination of subtle phases not apparent to the eye. This finding shows that a class of materials, which all contain copper oxide and are known to exhibit a variety of subtle phases, may have even more complexity than thought. And, in fact, some phases are brought about not by changes in temperature but magnetic field.

One of the best tools for testing new materials for the next generation of research magnets is a MagLab magnet.

Examining the material samarium hexaboride, scientists discover seemingly contradictory properties and an exciting, new mystery for physicists.

This week at the lab, electrical engineers are updating the power supplies in the DC Field Facility. This is good news for scientists who conduct experiments in the resistive magnets there. After replacing some magnetic components in the supplies, the facility will have more power (which we need to fuel the more powerful magnets we are developing) as well as higher-quality power. That means stable electrical current with fewer and smaller ripples, which in turn generates a more stable magnetic field, which translates into more accurate measurements for scientists. In fact, the stability of the magnetic fields will increase by a factor of 10.

Need a visual? Imagine the maximum amount of direct current used at the lab represented as the height of a mountain, with a mile-high peak. Now imagine the ripple   — or “noise” — on the current as rocks and boulders on the sides of the mountain. The bigger the boulders, the bigger the noise. The upgrades to the power supply will allow us to reduce the size of those “noisy” boulders to barely discernible pebbles less than an inch high! To be a little more technical, it means a field stability for all our resistive magnets of 10 parts per million.

View this photo set on Flickr


Photos by STEPHEN BILENKY / Text by KRISTEN COYNE

Two researchers play with nanostructures in a fun, fertile physics playground: the space between two things.

Researchers working at the National MagLab have identified a material that behaves as a conductor and an insulator at the same time, challenging current understanding of how materials behave, and pointing to a new type of insulating state.

The work by Dagan et. al. explores the emergence and coexistence of superconductivity and magnetism at the interface between insulating, non-magnetic LaAlO3 and SrTiO3 nanowires at low temperatures. The effect of the antiparallel magnetic order on the resistance of the 50 nm wide patterned wires follows the form of giant magnetoresistance (GMR) at low applied magnetic fields.

A team of researchers from Université de Sherbrooke, Laboratoire National des Champs Magnétiques Intenses (LNCMI), University of British Columbia, Canadian Institute for Advanced Research and the National High Magnetic Field Laboratory discovered a previously unobserved portion of the Fermi surface in underdoped YBCO. This discovery provides further evidence to support the picture of the Fermi surface being reconstructed as a result of charge density wave order developing in underdoped YBCO prior to the material entering the superconducting state at lower temperatures.

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