Author: Jason Hancock

Physics student John Mangeri wins prestigious fellowship

John Mangeri’s Award Lands Him in Argonne National Laboratory

John Mangeri (left) with his SCGSR-award host Dr. Olle Heinonen (right) in front of the Chemistry building (bldg. 200) at Argonne National Laboratory. (Photo credit to Dr. Andrea Jokisaari)

John Mangeri (left) with his SCGSR-award host Dr. Olle Heinonen (right) in front of the Chemistry building (bldg. 200) at Argonne National Laboratory.
(Photo credit to Dr. Andrea Jokisaari)

By Katherine Eastman

John Mangeri, a Ph.D. candidate in Dr. Serge Nakhmanson’s “Complex Materials by Computational Design” group, was selected to receive the U.S. Department of Energy’s Office of Science Graduate Research (DoE SCGSR) award for his project, Computational Design of Functional Materials for Electrothermal Energy Interconversion on Mesoscale.

This award allowed John to conduct research on his project at the Argonne National Laboratory in Lemont, IL, for from June to September in 2016 under the guidance of the DoE collaborator, Dr. Olle G. Heinonen.

The U.S. Department of Energy states that the “SCGSR program provides supplemental awards to outstanding U.S. graduate students to pursue part of their graduate thesis research at a DoE laboratory in areas that address specific challenges central to the Office of Science mission.”

Argonne National Laboratory is one of the U.S. Department of Energy’s premier national laboratories for scientific and engineering research. Its state-of-the-art, high-performance computing facilities that were available to John during his visit enabled him to achieve rapid progress in advancing his Ph.D. project.

“I am extremely pleased with John’s research accomplishments on the way to his Ph.D. degree. John is currently the main code developer for the mesoscale-level multiphysics simulation package, ‘Ferret,’ that is being utilized by the group together with our Argonne collaborators to design new materials that can convert thermal energy into electrical and vice versa,” Dr. Nakhmanson commented.

John’s research on a new material concept for this energy conversion by utilizing an electrocaloric effect that changes the temperature of a dielectric when subjected to an external electric field was recently published in a new journal, NPJ Computational Materials, that is partnered with the prestigious scientific journal Nature. The article, entitled “Amplitudon and phason modes of electrocaloric energy interconversion,” was co-authored by John, Krishna Pitike (also a graduate student in Dr. Nakhmanson’s group), Dr. Pamir Alpay, and Dr. Nakhmanson.

In that project, the co-authors conducted a theoretical investigation of a model system made up of thin perovskite-oxide crystal layers, whose polarization directions can be easily reoriented by an applied electric field.

This unusual system, the team demonstrated, must exhibit two different kinds of electrocaloric responses, conventional and anomalous one, that can either heat the material up or cool it down with a capability to switch between these two modes on demand. Possible applications for this effect are new, integrated cooling sources for computer chips and other electronic circuits, as well as more efficient and silent HVAC devices.

“The effect we saw was quite unexpected. We were able to show that there are two kinds of energy conversion modes in that material — stemming, respectively, from either amplitudon or phason excitations of the local polar dipoles,” John said.

Even though this material does not yet exist, he further explained, quantum mechanics suggests that it could be put together by one of atomic layer-by-layer deposition techniques that are utilized for growing thin oxide films on substrates.

“It’s a good opportunity for me,” John said in reflection of his SCGSR-sponsored research experience at Argonne. “There’s always more work to do — you always have to be looking at the next step in developing your career and being exposed to a different setting for doing science really helps with evaluating your priorities.”

Physics society names three APS Fellows

The American Physical Society (APS) has named three UConn Physics faculty as APS Fellows. APS Fellowship is a distinct honor signifying recognition by one’s professional peers and is an honor bestowed by election. The criterion for election is exceptional contributions to the physics enterprise; e.g., outstanding physics research, important applications of physics, leadership in or service to physics, or significant contributions to physics education.

In 2016, George Gibson, George Rawitscher, and Alan Wuosmaa are named Fellows of the American Physical Society.

APS Fellow George Gibson: For deepening our understanding of molecules in strong fields

APS Fellow George Rawitscher: “For pioneering contributions to the development of the continuum discretized coupled channels method for including the coupling to break-up channels in three-body models of deuteron elastic scattering, break-up and stripping and for his deep studies of the role of nonlocality in the nucleon-nucleus optical potential.”

APS Fellow Alan Wuosmaa: “For essential contributions to nuclear physics over a wide range of topics including the demonstration of the nonexistence of positron lines in collisions with very heavy nuclei at the Coulomb barrier, the nature of cluster structures in nuclei, studies of particle multiplicities in relativistic heavy-ion collisions, and the exploration of single-particle properties of light exotic nuclei.”

gibson                  

Welcome to Three Assistant Professors in Astronomy

The Physics department is pleased to announce a new thrust in research, scholarship and teaching with the hire of three young astronomers:

Jonathan Trump arrives from a Hubble Space Telescope Fellowship at Penn State University, Cara Battersby who currently has an NSF fellowship at the Harvard Smithsonian Center for Astrophysics and Katherine Whitaker Tease who is currently completing a Hubble Space Telescope Fellowship at UMass. Both Kate and Cara will take a one-year leave to finish their current appointments and they will be on campus full time starting Fall 2017.

Welcome astronomers!

 

Professor William Stwalley Retires

William C. Stwalley (Bill), Board of Trustees Distinguished Professor of Physics, has retired from teaching on June 1, 2016. He is now continuing as UConn Board of Trustees Distinguished Professor Emeritus /Research Professor of Physics and also continuing as an Affiliate Professor of Chemistry and of the Institute of Material Science (IMS).

The Physics Department would like to give a heartfelt ‘Thank You!’ and ‘Congratulations!’ to Cynthia, Michael and Bill.
Enjoy your much deserved retirement!

UConn Physics welcomes new teaching faculty

Assistant professors in residence (APiRs) are primarily responsible for teaching and managing large introductory service classes in cooperation with faculty.

The Physics Department has recently promoted Diego Valente to APiR from his former position of Visiting Assistant Professor. Congratulations Diego on a well-deserved promotion.

The department extends a warm welcome to three other APiRs, Belter Ordaz-Mendoza, Hani Duli, and Xian Wu, who are recently recruited to help advance our growth initiatives.

 

 

“Caution: Shrinks When Warm”

Sahan Handunkanada, holds a crystal sample on Sept. 22, 2015. (Peter Morenus/UConn Photo)

 – Kim Krieger – UConn Communications

Jason Hancock, Assistant Professor in Physics, with graduate students, Erin Curry and Sahan Handunkanda, have been investigating a substance that shrinks when it warms.

Most materials swell when they warm, and shrink when they cool. But UConn physicist Jason Hancock has been investigating a substance that responds in reverse: it shrinks when it warms.

Although thermal expansion, and the cracking and warping that often result, are an everyday occurrence – in buildings, bridges, electronics, and almost anything else exposed to wide temperature swings – physicists have trouble explaining why solids behave that way.

Research by Hancock and his colleagues into scandium trifluoride, a material that has negative thermal expansion, recently published in Physical Review B, may lead to a better understanding of why materials change volume with temperature at all, with potential applications such as more durable electronics. For the complete article in UConn Today that explains their findings, see “Caution: Shrinks When Warm” .

Physicists Solve Low-Temperature Magnetic Mystery

 – Tim Miller

Researchers have made an experimental breakthrough in explaining a rare property of an exotic magnetic material, potentially opening a path to a host of new technologies. From information storage to magnetic refrigeration, many of tomorrow’s most promising innovations rely on sophisticated magnetic materials, and this discovery opens the door to harnessing the physics that governs those materials.

The work, led by University of Connecticut professor Jason Hancock, and Ignace Jarrige of the Brookhaven National Laboratory, marks a major advance in the search for practical materials that will enable several types of next-generation technology. A paper describing the team’s results is published this week in the journal Physical Review Letters.

The full text of this article can be found on the UConn Today website at “Physicists Solve Low-Temperature Magnetic Mystery”.