This week at the lab, we're trying a magnet on for size.
A research magnet is made of a set of coils engineered from a current-carrying material — a fancy version of the electromagnet many kids make in school using a wire, battery and nail. Typically, four or five coils are slid one inside the next like Russian nesting dolls.
This week, we're slipping the second coil of the highly anticipated 32 tesla all superconducting magnet over the inner-most coil, then making any necessary adjustments. Like a good pair of jeans, the fit should be snug but not tight, with a mere millimeter between the two coils.
"Assembling the coils and the entire electrical circuit is an intricate job, and an exiting one," said project leader Huub Weijers. "After almost seven years of development, design, testing and construction of components, the final magnet is taking shape in front of our eyes."
These two coils, which contain about 6 miles of superconducting tape made of the novel, high-temperature superconductor yttrium barium copper oxide (YBCO). But YBCO is only one layer in this magnet. Those coils will soon be nested inside five more of coils made of conventional superconductors, three of niobium-tin and two of niobium-titanium.
The finished, 2.3-ton magnet system, when completed this summer, will join the MagLab’s roster of world-record magnets. At 32 tesla, it will be by far the strongest superconducting user magnet in the world, surpassing the current record of 23.5 tesla.
"It’s a difficult task to work through the many details of a new technology," said the magnet's lead designer Adam Voran, who managed the computer modeling for the project. "But the reward of seeing those meticulous designs being born into a tangible reality is exhilarating."
Photo by Stephen Bilenky / Text by Kristen Coyne.
This week at the lab, Peng Chen starts a new job at the Applied Superconductivity Center (ASC), where he will contribute to developing a groundbreaking magnet with bismuth-strontium-calcium-copper-oxide (Bi-2212), a promising high-temperature superconductor.
Chen's new job sounds a lot like his old job: building a groundbreaking magnet at the ASC with Bi-2212. The main difference is that last week, Chen was still a graduate research assistant. This week, he is a postdoctoral research associate, having graduated Saturday from Florida State University (FSU) with a Ph.D. in mechanical engineering.
"I can relax a little bit," laughed Chen, who has put in long hours over the past several months writing and revising his thesis.
In addition to designing and building world-record magnets used by scientists from across the globe, the MagLab has an important educational mission. This includes training early-career scientists like Chen. It's not by accident that undergraduates, graduate students and postdocs make up 40 percent of the lab's staff.
Since arriving here from China five years ago, Chen has experienced an intense, hands-on education among the team building a Bi-2212-based, high-field, high-homogeneity nuclear magnetic resonance magnet dubbed the Platypus. ASC Director David Larbalestier, who is Chen's advisor, said Chen has shown a lot of grit in the face of tough technical problems that come with building a first-of-its-kind instrument. In fact, ASC is hoping to get a patent out of a fully superconducting joint Chen built for the Platypus.
"He combines an engineering viewpoint with a strong desire to understand what he is doing, which makes his approach to complex technical problems very valuable," said Larbalestier, who placed the blue doctoral hood on Chen during his graduation ceremony to signify his former student’s new status.
Chen said he is looking forward to his new role on the team.
"In the transition from student to postdoc, you have more freedom," said Chen. "It's not only about your dissertation; you have more choices to do different aspects of the project and to collaborate with other teammates to support them — take more responsibility. I have a feeling I will do more and broaden my duties."
Text by Kristen Coyne / Photo courtesy of Peng Chen.
This week at the lab, scientists are using a brand new tool to tweak the crystal structure of materials in the hopes of imbuing them with potentially useful properties.
Using a technique called pulsed laser deposition, physicist Christianne Beekman is creating thin films of materials less than 100 nanometers thick — one one-thousandth the thickness of a sheet of paper. The process involves vaporizing a target material with a class 4 laser, generating a colorful plume of plasma. When that plasma settles on a waiting piece of substrate, the result is a thin film that alters the original structure of the material in a way that can induce new magnetic or electrical properties.
“Sometimes in these complex materials a slight change in the interatomic distance could tip it over to an entirely different phase,” said Beekman. The original “bulk” material might, for example, change from a metal to an insulator in its thin film form (or vice versa) – a nifty trick with potentially powerful applications in electronics and computers. Beekman is also looking at materials that might make excellent solar cells, if photons hitting thin-film versions of them turn out to generate more than one electron per photon.
After creating thin films in this new instrument, Beekman and her team will use MagLab magnets and other facilities to investigate their properties.
“The ability to grow high-quality complex oxide thin films allows us to accelerate materials discovery,” said Beekman, “which will lead to the technologies of tomorrow.”
Video by Stephen Bilenky / Text by Kristen Coyne
Experiment marks first time an iron-based high-temperature superconductor works as a strong magnet.
Reduced-size prototype coils for the 32 T all-superconducting magnet have been successfully tested. The results include the generation of 27 T, which is a record for superconducting magnets.
An understanding of the formation mechanism of endohedral metallofullerenes may pave the way towards targeted synthesis of these nanomaterials, which are attractive for use in biomedicine and renewable energy. Their bottom-up synthesis is investigated and charge transfer from the encapsulated metal to carbon cage is determined to play a key role in formation.
Targeted theranostic nanovehicles are capable of targeting cerebrovascular amyloid associated with Alzheimer’s Disease and serving as early diagnostic and therapeutic agents across multiple imaging modalities. Assessed in animal models at 21.1 T, these nanovehicles were loaded with gadolinium-based magnetic resonance imaging (MRI), iodine-based single photon emission computerized tomography (SPECT) or fluorescent contrast agents as well as anti-inflammatory and anti-amyloidogenic pharmaceuticals to demonstrate targeted enhancement and treatment in cerebral amyloid angiopathy.
Researchers using pulsed field gradient NMR at the AMRIS facility found clear evidence for molecular single file diffusion of xenon gas confined inside model nanotube systems.