Developing New Magnetic Materials

Synthesizing and testing manganese gallium samples for spintronic applications.

Developing New Magnetic Materials
Stephanie Bauman, an intern in the Materials Process Center and Center for Materials Science and Engineering's 2017 Summer Scholar program, holds a sample of manganese gallium, a new material known as an antiferromagnet, that can serve as the basis for long lasting, spintronic computer memory devices. She worked in the lab of assistant professor of electrical engineering Luqiao Liu. Photo: Denis Paiste/Materials Processing Center

MIT scientist Luqiao Liu, the assistant professor is developing new magnetic materials for long-lasting, spintronic computer memory. The magnetic materials called antiferromagnets can work at room temperature by reversing their electron spin.

Stephanie Bauman, an intern in the Materials Processing Center said, “In our project, we’re working on the area of spintronics, anti-ferromagnetic devices that switch electron spin controlled by a current. I’m working with a lot of new equipment like the vibrating sample magnetometer and the sputterer to lay down thin films.”

Developing New Magnetic Materials
Intern Stephanie Bauman worked with antiferromagnets and spintronic computer memory devices, which operate by reversing electron spin at room temperature.
Photo: Denis Paiste/Materials Processing Center

“I’ve been working on a daily basis with Joe Finley, who is a graduate student here, and he’s been an explaining a lot of things to me. It’s a very dense subject matter. And he does help me out a lot when we go to things like the X-ray diffraction room, and he shows me how the graphs can interpret how thick each layer of the thin layers of the devices are. He’s really helpful and easy to work with.”

Liu primarily synthesized the thin films by using a sputter deposition chamber. Taking out a sample from the machine, she then followed the complicated set of steps to organize the parts in the main chamber. As the chamber was pressurized, she had to bring it back to everyday atmospheric pressure before taking it out.

Developing New Magnetic Materials
2017 MPC-CMSE Summer Scholar Stephanie Bauman presents her poster on her internship in the lab of assistant professor of electrical engineering Luqiao Liu.
Photo: Denis Paiste/Materials Processing Center

Bauman said, “Due to disengagement, I can see with the sample holder on a moveable arm, the device is able to rotate around.”

“It moved across a gear arm out of the main chamber into transfer chamber known as a load lock. A very, very important part of this is to make sure you close the transfer valve again, otherwise, you mess up the pressure in the main chamber.”

The prototype of the magnetic material is really tiny, almost half a centimeter by a half a centimeter.

“While losing the screws on the arm, we need to be careful as it may cause a scratch to the sample. Once safely removed, we placed it in a special holder, labeled based on when each sample was made, which sample of the day it is and its thickness. That way, we can refer back to that in our data so that we know what thickness levels that we’re testing.”

Baumen then explained, how a new sample is loaded into the sputterer device. She said, “Carefully tighten the screw, making sure not to torque it too much, then you move the other arm into place. Once both arms were tightened on the sample holder, she was able to put the sample into the load lock.”

“Very simple just make sure it’s lined up correctly. It’s also important to make sure the O-ring is clean, and so is the lid before you put it back on. That way there’s a very good seal. So that’s really it for the loading, and then you just turn the vacuum pumps back on and wait until it reaches the appropriate pressure and then loads it into the main chamber.”

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