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Growing up in Coeur d’Alene, Idaho, with parents in engineering who were employed in the state’s silver mining sector, MIT senior Maria Aguiar cultivated an early enthusiasm for materials. The star garnet, the state’s precious mineral, remains her favorite. It’s purely coincidental, however, that her undergraduate dissertation also revolves around garnets.
Her investigation delves into methods to adjust the magnetic characteristics of garnet thin films — research that could enhance data storage technologies. After all, Aguiar notes, a significant portion of technology and energy applications increasingly depends on utilizing materials with advantageous electronic and magnetic traits.
Enthralled by engineering during high school — science fiction was also her passion — Aguiar applied to MIT and was accepted. However, she had only discovered materials engineering through an online search. She thought she would lean toward aerospace engineering, astronomy, or even physics, disciplines that had captivated her curiosity at different times.
Initially uncertain about her major, Aguiar began to recognize that her interests consistently centered around materials. “I would explore an aerospace museum and would find myself more intrigued by the tiles used in the shuttle to withstand heat. I was fascinated by the process of engineering such materials,” Aguiar recalls.
It was a first-year pre-orientation program (FPOP), designed to allow new students to sample different majors, that convinced Aguiar that materials engineering suited her passions. It certainly helped that the students from DMSE were welcoming and approachable. “They were enthusiastic about their major and eager to discuss their work,” Aguiar says.
During the FPOP, Associate Professor James LeBeau, a DMSE specialist in transmission electron microscopy, inquired about students’ interests. When Aguiar expressed her love for astronomy, LeBeau likened it to microscopy.
“An electron microscope is merely a telescope in reverse,” she remembers him saying. Instead of surveying something distant, you shift from large to small — zooming in to discern intricate details. That analogy resonated with Aguiar and motivated her to embark on her first Undergraduate Research Opportunities Program (UROP) project with LeBeau, where she gained further insight into microscopy.
Attracted to magnetic materials
Class 3.152 (Magnetic Materials), instructed by Professor Caroline Ross, ignited Aguiar’s fascination with magnetic materials. The subject matter was riveting, Aguiar states, and she realized that related research would significantly impact contemporary data storage technology. After starting a UROP in Ross’s magnetic materials lab in the spring of her junior year, Aguiar became engrossed, and the work ultimately developed into her undergraduate thesis, “Effects of Annealing on Atomic Ordering and Magnetic Anisotropy in Iron Garnet Thin Films.”
The overarching aim of her work was to comprehend how to manipulate the magnetic properties of materials, such as anisotropy — the phenomenon where a material’s magnetic attributes vary based on the direction in which they are assessed. It appears that altering the positions of certain metal atoms — or cations — within the garnet’s crystalline structure can affect this directional behavior. By meticulously arranging these atoms, researchers can “tweak” garnet films to offer innovative magnetic characteristics, paving the way for the advancement of materials in electronics.
Upon joining the lab, Aguiar began collaborating with doctoral candidate Allison Kaczmarek, who was examining the link between cation ordering and magnetic properties for her PhD thesis. Specifically, Kaczmarek was investigating the growth and characterization of garnet films, testing various methods to induce cation ordering by adjusting the settings in the pulsed laser deposition process — a method that blasts a laser at a target material (in this case, garnet), vaporizing it to deposit onto a substrate, such as glass. Modifying parameters such as laser energy, pressure, and temperature, along with the composition of mixed oxides, can dramatically affect the resulting film.
Aguiar focused on one particular parameter: annealing — subjecting a material to elevated temperatures before cooling. This strengthening method is commonly employed to transform the arrangement of atoms within a substance. “So far, I have discovered that when we anneal these films for durations as brief as five minutes, the film approaches a preference for out-of-plane magnetization,” Aguiar states. This attribute, termed perpendicular magnetic anisotropy, is vital for magnetic memory applications due to its benefits in performance, scalability, and energy efficiency.
“Maria has been extremely dependable and quick to take initiative. She absorbs information rapidly and is very considerate about her work,” Kaczmarek comments. That thoughtfulness was evident early on. When tasked with identifying an optimal annealing temperature for the films, Aguiar didn’t merely conduct tests — she first performed an exhaustive literature review to grasp what had been previously explored, then meticulously tested films at varying temperatures to ascertain which worked best.
Kaczmarek first became acquainted with Aguiar as a teaching assistant for class 3.030 (Microstructural Evolution of Materials), instructed by Professor Geoffrey Beach. Even before starting the UROP in Ross’s lab, Aguiar had communicated a clear research aspiration: to acquire hands-on experience with advanced techniques such as X-ray diffraction, vibrating sample magnetometry, and ferromagnetic resonance — methods typically employed by more experienced researchers. “That’s a goal she has certainly accomplished,” Kaczmarek remarks.
Outside the lab, beyond MIT
Beyond the lab, Aguiar merges her love for materials with a strong commitment to community outreach and social cohesion. As co-president of the Society of Undergraduate Materials Scientists in DMSE, she assists in organizing events that foster inclusivity within the department. Class dinners are enjoyable — many seniors recently visited a Cambridge restaurant for sushi — and “Materials Week” every semester primarily serves as a recruitment initiative for new students. A hot cocoa gathering around the winter holidays combined seasonal festivities with class evaluations — tedious for some, perhaps, but essential for enhancing instruction.
After graduating this spring, Aguiar is eager to pursue graduate studies at Stanford University and has set her sights on a teaching career. She cherished her time as a teaching assistant for the popular first-year classes 3.091 (Introduction to Solid-State Chemistry) and 3.010 (Structure of Materials), earning an undergraduate student teaching award in the process.
Ross is confident that Aguiar is a strong candidate for graduate studies. “For graduate school, you require academic excellence and practical skills like proficiency in the lab, and Maria possesses both. Then there are the soft skills, which relate to your organizational abilities, resilience, and management of diverse responsibilities. Typically, students develop these over time, but Maria is well ahead of the game,” Ross asserts.
“One factor that makes me optimistic about Maria’s time in graduate school is that she has a wide-ranging interest in many aspects of materials science,” Kaczmarek adds.
Aguiar’s enthusiasm for the field extended to a creative side project: a DMSE-exclusive “Meow-terials Science” T-shirt she crafted — featuring cats performing iconic lab experiments — was a favorite among students.
She remains perpetually intrigued by the materials around her, even in the water bottle she uses daily. “Studying materials science has transformed my perspective on the world. I can pick up something as mundane as this water bottle and contemplate the metallurgical processing techniques I learned in class. I simply adore that there’s so much to glean from the everyday,” she concludes.
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