Nav: Home

Pushing the (extra cold) frontiers of superconducting science

October 18, 2018

Measuring the properties of superconducting materials in magnetic fields at close to absolute zero temperatures is difficult, but necessary to understand their quantum properties.

How cold? Lower than 0.05 Kelvin (-272°C).

"For many modern (quantum) materials, to properly study the fine details of their quantum mechanical behavior you need to be cool. Cooler than was formerly thought possible," said Ruslan Prozorov, a physicist at the U.S. Department of Energy's Ames Laboratory, who specializes in developing instrumentation which measures just such things.

Prozorov and his research team have developed a method to measure magnetic properties of superconducting and magnetic materials that exhibit unusual quantum behavior at very low temperatures in high magnetic fields. The method is being used to study quantum critical behavior, mechanisms of superconductivity, magnetic frustration and phase transitions in materials, many of which were first fabricated at Ames Laboratory.

They did so by placing a tunnel diode resonator, an instrument that makes precise radio-frequency measurements of magnetic properties, in a dilution refrigerator, a cryogenic device that is able to cool samples down to milli-Kelvin temperature range. While this was already achieved before, previous works did not have the ability to apply large static magnetic fields, which is crucial for studying quantum materials.

Prozorov's group worked to overcome the technical difficulties of maintaining high-resolution magnetic measurements, while at the same time achieving ultra-cold temperatures down to 0.05 K and in magnetic fields up to 14 tesla. A similar circuit has already been used in a very high magnetic field (60 T) when the team performed the experiments at Los Alamos National Lab.

"When we first installed the dilution refrigerator, the joke was that my lab had the coldest temperatures in Iowa," said Prozorov, who conducts his research where Midwestern winters are no laughing matter. "But we were not doing this just for fun, to see how cold we could go. Many unusual quantum properties of materials can only be uncovered at these extremely low temperatures."

The group studied pairing symmetry in several unconventional superconductors, mapped a very complex phase diagram in a system with field-induced quantum critical behavior, and recently uncovered very unusual properties of a spin-ice system, "none of which would be possible without this setup," said Prozorov.
The research is further discussed in the paper, "Tunnel diode resonator for precision magnetic susceptibility measurements in a mK temperature range and large DC magnetic fields," authored by H. Kim, M.A. Tanatar and R. Prozorov; and published as an Editor's Pick in the Review of Scientific Instruments.

Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems.

DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit

DOE/Ames Laboratory

Related Magnetic Fields Articles:

Visualizing strong magnetic fields with neutrons
Researchers at the Paul Scherrer Institute PSI have developed a new method with which strong magnetic fields can be precisely measured.
Scientists deepen understanding of magnetic fields surrounding Earth and other planets
Now, a team of scientists has completed research into waves that travel through the magnetosphere, deepening understanding of the region and its interaction with our own planet, and opening up new ways to study other planets across the galaxy.
Technique pulls interstellar magnetic fields within easy reach
A new, more accessible and much cheaper approach to surveying the topology and strength of interstellar magnetic fields -- which weave through space in our galaxy and beyond, representing one of the most potent forces in nature -- has been developed by researchers at the University of Wisconsin-Madison.
A bubbly new way to detect the magnetic fields of nanometer-scale particles
The method provides manufacturers with a practical way to measure and improve their control of the properties of magnetic nanoparticles for a host of medical and environmental applications.
Quantum sensing method measures minuscule magnetic fields
A new technique developed at MIT uses quantum sensors to enable precise measurements of magnetic fields in different directions.
The FASEB Journal: Magnetic fields enhance bone remodeling
Since the creation of 3D-printed (3DP) porous titanium scaffolds in 2016, the scientific community has been exploring ways to improve their ability to stimulate osteogenesis, or bone remodeling.
Tangled magnetic fields power cosmic particle accelerators
Magnetic field lines tangled like spaghetti in a bowl might be behind the most powerful particle accelerators in the universe.
Growing magnetic fields in deep space: Just wiggle the plasma
Astrophysicists have long wondered how cosmic magnetic fields fields are produced, sustained, and magnified.
Surprise finding: Discovering a previously unknown role for a source of magnetic fields
Feature describes unexpected discovery of a role the process that seeds magnetic fields plays in mediating a phenomenon that occurs throughout the universe and can disrupt cell phone service and knock out power grids on Earth.
Neutrons scan magnetic fields inside samples
With a newly developed neutron tomography technique, an HZB team has been able to map for the first time magnetic field lines inside materials at the BER II research reactor.
More Magnetic Fields News and Magnetic Fields Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.