Los Alamos National Laboratory

Los Alamos National Laboratory

Delivering science and technology to protect our nation and promote world stability

Lab Character

A monthly profile series featuring a Lab employee who exemplifies one of 9 traits identified in the Laboratory’s Purpose Statement

Lab Character: Who We Are

Priscila Rosa

Priscila Rosa

Putting the pressure on to expand scientific possibilities

Priscila Rosa knows the importance of applying pressure to achieve goals. That’s how she summoned the drive to leave Brazil, her home country, for a joint postdoctoral fellowship in the United States. Now a materials physicist in Condensed Matter and Magnet Science (MPA-CMMS), Rosa applies pressure and magnetic fields to understand how materials behave in extreme environments.

She is the principal investigator of an early career Laboratory Directed Research and Development (LDRD) project using pressure to measure thermal expansion in quantum materials. This fundamental understanding is essential to ultimately knowing how to control and tailor such materials for potential applications.

The LDRD project satisfies a personal goal of Rosa’s to explain how and why things work.

“The knowledge gained from fundamental research is priceless. It allows you to understand things so well that you can predict and control phenomena,” she says. “I’m at the Lab because I believe in the power of fundamental research.”
Emilio Racinez

Priscila Rosa aligns a single crystal in an x-ray diffractometer to determine the properties of its crystalline lattice.

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Rosa joined a group perfect for the task. MPA-CMMS has a distinguished record of supporting the Lab’s national security science mission through fundamental materials discoveries. These contributions started with post-World War II experiments that determined the properties of the newly created element plutonium.

They continue with recent breakthroughs such as the discovery of the first plutonium-based unconventional superconductor, the detection of the long-sought nuclear magnetic resonance signature of plutonium-239, and the first-ever resolution of delta plutonium’s electronic ground state.

As a member of the group’s Strongly Correlated Electron Systems team, Rosa synthesizes single crystals — a delicate process crucial to understanding a material’s basic properties — and explores those crystals under pressure. She focuses on correlated electronic systems based on f electrons, a renowned area of leadership for Los Alamos.

Electrons in conventional metals and semiconductors, e.g., copper and silicon, act independently. In correlated materials containing d- or f-electron incomplete shells, about 1,023 electrons interact strongly with each other, creating complex, emergent ground states — plutonium being a classic example.

Priscila is unique in the sense that she works in two realms: sample synthesis and characterization,” says Mike Hundley, MPA-CMMS group leader. “She’s built up great intuition for sample growth and for what combinations of elements could lead to materials that support new discoveries.”

Rosa is the principal investigator for two LDRD projects and participates in two other Department of Energy projects, all aimed at investigating quantum materials — a class of materials that promise to revolutionize energy — and security relevant technologies.

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Priscila Rosa and Nakheon Sung, a Director's Fellow postdoc, discuss the principles of optical thermal expansion measurements as Priscila transfers liquid nitrogen to the equipment she uses to perform such measurements under applied pressure. An optical fiber can be seen at the top of the apparatus.

To do this she has developed novel experimental techniques and diagnostics tools. For example, her first project as a Director’s Postdoctoral Fellow resulted in a general principle for using hydrostatic pressure to force cerium-based superconductors to nucleate a magnetic phase.

Last year she proved that optical fiber sensors can be used to measure the thermal expansion of these superconductors under pressure. This has led to her early-career LDRD project that uses applied pressure as a “tuning knob” to define the thermal expansion of the strongly correlated superconductor CeRhIn5 at the point with the largest quantum fluctuations.

“Priscila’s foundational research has a common theme of discovering and understanding emergent quantum states of matter. It pushes the forefront of science and opens possibilities for new, quantum-based technologies,” says her mentor Joe Thompson (MPA-CMMS).

To further expand her contributions to the Lab’s energy security efforts, she submitted an LDRD proposal with Jinkyoung Yoo (Center for Integrated Nanotechnologies, MPA-CINT) to investigate f-based nanowires, which are predicted to host unusual particles that enable quantum computing. By measuring the electrical properties of these strongly correlated nanowires, the team aims to detect these particles for the first time in an f-electron-based material.

Their LDRD proposal was a winner, they learned just recently, and they plan to begin working on this new exciting path in October 2018.

“Priscila has a particularly curious mind which is reflected, in part, by the breadth of research that she leads,” says Thompson. “She is committed to the success of her peers, the organization, and her own work, no matter how daunting the challenges.”