Making magnets

Graduate and undergraduate students at Oregon State University are helping to break new ground for the next generation of high-performance electronic components and memory storage. The Applied Magnetics Lab is partnering with industry to bring major improvements to consumer products like cell phones and computers with better performing inductors and memory devices using advanced magnetic materials. The potential for impact of this work is evident from the ubiquity of these products — there are 2.5 billion (and growing) cell phones and computers in use today.

Students in the Applied Magnetics Lab experience a comprehensive and atypical education, said Pallavi Dhagat, associate professor of electrical engineering and co-director of the lab.

“Being on the cutting-edge of technology means that no one else has done it before, so you have to do everything, including sometimes building the instruments that characterize the new materials,” Dhagat said. “So, our graduate students are very well-rounded. They do everything from making the materials, creating the measurement systems, designing circuits and mechanical components for devices, writing programs to control the instruments and testing the materials.”

And there is plenty for undergraduates to do, too. Hannah Marvin, an electrical and computer engineering student, has been working with Ben Buford, a doctoral student, on creating and testing magnetic materials for cell phone inductors and magnetic memory devices.

“It’s wonderful to have her help,” Buford said. “It lets me focus on the higher level aspects of the research, such as designing the experiments and the theory behind the data processing.”

One of the tasks Buford has trained Marvin to do is called sputtering — a process by which films as thin as 10 nanometers are deposited on a silicon wafer. Sputtering is performed in a vacuum chamber filled with argon gas. Marvin places a wafer at the top of the chamber, and applies an electric current to create argon plasma. She then biases the target with a negative charge, which accelerates the ions in the plasma. The ions slam into the target material at the bottom of the chamber, knocking off atoms and depositing them onto the wafer.

Video: Graduate student, Ben Buford, describes how the Applied Magnetics Lab uses a Kerr Effect Microscope.

Marvin also has learned how to use a Kerr effect microscope, one of the characterization instruments that was built in the lab. The films they are working with contain such small amounts of magnetic material that many instruments are not sensitive enough to characterize the magnetic properties. The Kerr effect microscope uses polarized light which reveals differences in magnetization when it is reflected off the surface of the material. Marvin’s task has been to take magnetic images of the material through the microscope under different controlled conditions.

“My friends ask me all the time if the lab work is fun, and I tell them that the actual doing of it isn’t all that interesting, but the concept behind it and applications that it can be used for are just amazing,” said Marvin, who plans to continue pursuing her interest in microelectronics after she graduates.

In the meantime, Marvin is gaining valuable hands-on experiences through the lab work. She was responsible for building a device to regulate the temperature of the samples while they are being analyzed under the Kerr effect microscope.

“I really liked building the temperature controller because it was unlike any classroom project, where you are given step-by-step instructions,” she said. “For this, I had to read the manuals for the Peltier plate, the temperature controller and the probe, to figure out how they had to be connected so that I wouldn’t destroy anything.”

Even though Marvin dropped a Peltier plate, which sheared in half when it hit the floor, the project was a success. Another researcher in the lab quickly borrowed the temperature controller for their research.

Working in the lab has opened up a whole new world for Marvin. She recalled that when she first joined the lab, the presentations she attended from the group went way over her head, but she had a different experience recently at a thesis defense.

“I actually understood the majority of what they were talking about, and that was the first time that I had any perspective on how much I’ve been learning. So that was really cool,” she said.

Buford is working with two undergraduates, including Marvin, on three projects, one of which is his thesis that he hopes to finish in 2016. Dhagat said that, in addition to Buford’s technical skills, he is a very good supervisor.

“Hannah could not have asked for a better mentor than Ben. He is just one of those remarkable students who is good at everything,” Dhagat said. Buford values the broad experience he has received in the lab, and plans to apply his acquired skills and his ability to problem-solve new technologies to a job in industry.

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