Students conduct research on magnetism

By Benjamin Welch

Tucked away in the catacomb-like walkways of Ross Hall, Robin Macaluso, a professor of chemistry, and her students perform a plethora of research tasks in a laboratory that, upon first glance, resembles a maintenance closet.

UNC chemistry students work in a Ross Hall lab.

Han Hong, left, a chemistry graduate student, and Kyle Treadway, a junior chemistry major, observe the quality of their praseodymium compound in an arc welder Wednesday in Ross Hall. Photo by Benjamin Welch

Preparing the lab and creating the compound – 1:07 p.m.
Though their research is primarily for educational purposes, Macaluso and her students occasionally stumble upon unknown metallic compounds.

“Some people intentionally do the synthesis of novel compounds. So it’s not that everyone does it,” said Macaluso, whose focus is primarily on magnetism, the structure of magnets and super conductivity. “Some people, for example, are really good at measuring magnetic properties and getting structural information. Some people focus on synthesis. So everybody has their own piece of the puzzle, and we work together. Our contribution is synthesis of novel or already known compounds and identifying what that structure is. Obtaining that structural information isn’t necessarily easy.”

Though the students only gather once a week for two or three hours, the amount of pre-laboratory research can be extensive.

As an undergraduate, Kevin Treadway, a junior chemistry major, said he does not have much work out of class to complete; however, Han Hong, a graduate student studying chemistry, said he has to read five or six scholarly articles to prepare for his time in the laboratory.

Praseodymium, copper 2 and indium are placed next to each other to create a small conglomerate of metals, which then needs to be melted down and combined.

Process of research – 1:20 p.m.
Each week, three students gather in a laboratory on the first floor of Ross Hall to compress compounds and conduct research.

The process by which the students conduct the research, surprisingly, is not confusing. The metals are placed in an arc welder, which uses a power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point.

Treadway then carefully welds the compounds together to make a button of metals.

“Pure research,” Treadway said. “One day it could lead to something practical. We study the compounds and find out the right ratios for some conductors that could be used in an industry later on. But for now it’s research groundwork.”
While using the arc welder, Treadway has to apply the correct amount of gases in the chamber to prevent the oxidation of the metals, which will turn them white and chalky during the process.

Post-creation – 1:32 p.m.
After the compound has been created, the students wrap it in tantalum foil and place it in a vial to be vacuum sealed and labeled.

“I make the inside a vacuum, without any oxygen or air, and put it in the oven for a couple weeks,” Hong said.
Sealing the compound – 1:46 p.m.

The vial, which contains the element and two rocks to block off oxygen, is welded shut by Hong to contain the vacuum seal. Afterward, Evan Sanders, a sophomore chemistry and business major, places the compound in an oven to bake at 500-600 degrees for about two weeks. Macaluso said at the conclusion of the baking, they use a technique to observe the material.

Analysis – 2:20 p.m.
“We have to find out what elements there are and what ratio,” Macaluso said. “And this is a solid, so we want to find out where the atoms are — what the structure is. Because this is a crystal structure, the technique to do this is called X-ray diffraction. So it’s essentially the same philosophy as when you go get a dental X-ray. That’s essentially a diffraction pattern of your teeth or bones, and we do the same thing.”

The research is done to synthesize materials and observe magnetic behavior that is novel to the material science community. Magnetic compounds have been used in cell phones and refrigerators, so the findings the UNC students make have the potential to expand technology.

“You spend a lot of time working, so each (project) has its own particular unique story,” Macaluso said.

Other than her research with her students, Macaluso has published numerous articles affecting the scientific community. She said she spends the majority of her time each day preparing for lectures, teaching and assisting students with research.

In “Nature of Materials,” a prestigious chemistry journal, Macaluso and her colleagues presented a high-risk proposal on a new route to describing magnetic behavior.

Though the research process is often tedious for the student scientists, an occasional previously undiscovered metallic compound with potential to excite the scientific community and advance technology is motivation to keep Macaluso and her students seeking answers.

Research resume
Additional works by Robin Macaluso, professor of chemistry, according to UNC School of Chemistry:
Goremychkin, E.A., Osborn, R., Rainford, B.D., Macaluso,R.T., Adroja,D.T., & Koza, M. “Spin Glass Order Induced by Dynamic Frustration”, Nature Physics,4,766 - 770, 2008.

Macaluso, R.T., Wells, D.M., Sykora, R.E., Albrecht-Schmitt, T.E., Mar, A., Nakatsuji, S., Lee, H., Fisk, Z.,& Chan, J.Y., "Structure and electrical resistivity of CeNiSb3", J. Solid State Chem. 177, 293–298, 2004.

Macaluso, R.T., Fisk, Z., Moreno, N.O., Thompson, J.D., & Chan, J.Y., "Structure and Magnetism of Ce5Pb3O", Chem. Mater. 16, 1560-1563, 2004.

Macaluso, R.T., Nakatsuji, S., Lee, H., Young, D.P., Fisk, Z.,& Chan, J.Y., "Synthesis, structure, and magnetism of a new heavy-fermion antiferromagnet CePdGa6", J. Solid State Chem. 174, 296-301,2003.