Bulent Sarlioglu is a professor of electrical and computer engineering at the University of Wisconsin-Madison. He studies electric motors, which engineers often call “electric machines,” with a focus on improving efficiency and power density. His work includes adapting new materials and techniques for electric motor design, spans hybrid and electric vehicles, aerospace and naval designs, and industrial applications.
Sarlioglu includes rare earth elements in his research and has given lectures on their importance in his field. In this Q&A, he discusses rare earth elements through his experience in working on electric motors.
Q: What are rare earths, and why are they critical for electric motors?
A: They are a group of 17 metallic elements. Fifteen of them are called lanthanides, and there are two others (scandium and yttrium). Despite the name, they are not actually scarce. The challenge is finding them in deposits large enough to extract and refine.
To show why these elements are important, we can look at electric motors. Many use magnets called neodymium-iron-boron, which are among the strongest commercially available permanent magnets in the world. Neodymium is a rare earth element.
There’s an element called dysprosium that is also used in these very strong magnets. It is extremely important because it allows these magnets to operate in very hot environments. Many electric and hybrid vehicle manufacturers use dysprosium in their motors. Conventional neodymium-iron-boron magnets typically have about an 80 degrees Celsius (or 176 degrees Fahrenheit) operational temperature. By adding dysprosium, you can reach 150 degrees Celsius (or 302 degrees Fahrenheit) or even higher operating temperatures.
We use neodymium-iron-boron magnets to make more efficient motors. Some car companies initially used induction machines (which create torque through the electromagnetic fields induced in the motor), but they’re typically less efficient than permanent-magnet machines.
That’s why permanent magnet motors use neodymium-iron-boron magnets to improve efficiency. If you make the motor more efficient, you can reduce energy consumption and hence need less lithium-ion battery for the same range. This reduces battery costs.
We also have these magnets in motors everywhere in our homes. They’re in our washing machines and dryers, in vacuum cleaners, fans and HVAC units. An enormous amount of power consumption in the United States goes to technology with electric motors in it. So, these elements extend beyond vehicles.
Q: Why is it important to find alternatives to rare earth elements?
A: There is a geopolitical element. For example, dysprosium can be several times as expensive as neodymium, depending on global supply and demand, and China controls most of its supply. It’s also a supply chain challenge. If you are planning to make tens of thousands of vehicles that need these elements but suddenly can’t get the magnets, you have to stop production.
As an alternative, we can use ferrites, which are also magnets, but weaker than neodymium magnets. When the second-generation Chevy Volt was in production, one of its two electric motors used ferrite-based magnets. Some vehicles use two motors for traction, a combination of induction and permanent magnet motors, which reduces the amount of these elements needed and lowers cost. In vehicles with both motor types, a control system blends their output depending on factors such as speed, power demand and road conditions.
There are other types of designs, like switched reluctance or synchronous reluctance motors, that don’t use permanent magnets at all. There is a lot of research in this area right now because rare earth elements are a major challenge. I hosted a special session at an IEEE conference in Houston, Texas, in 2025 and in Vancouver, Canada, in 2026 on rare-earth-free or rare-earth-reduced motor designs, and I invited experts from around the world. The room was full, and there were people standing outside the door to listen. There’s so much interest in this subject.
Q: What research are you pursuing to reduce rare earth element usage?
A: We had a five-year project from the U.S. Department of Energy to design a working motor without using dysprosium. We designed a traction motor that operated at or below 80 degrees Celsius (or 176 degrees Fahrenheit) right here at the University of Wisconsin-Madison. And we did that by laminating the magnets and trimming them to be very, very small. In a modern electric-vehicle motor, the magnets may be about 1 inch long. We reduced the permanent magnet’s axial length to about 2 millimeters and stacked them. This approach reduced eddy-current losses (wasted energy that turns into heat) in the permanent magnet and helped run the rotor at a lower temperature.
Another idea that we are researching is using high-speed machines, because if you speed up the motors, you can make them smaller for the same power output. If a motor is smaller, it does not require as much material for magnets. Alternatively, if we can improve cooling, we can reduce rare-earth use by lowering operating temperatures. We are working with Professor Gregory Nellis in mechanical engineering on cooling electric motors.
We are also starting to look at whether we can use ferrite with neodymium-iron-boron magnets. It’s like an Arnold Palmer drink that’s half tea and half lemonade. This is an optimization problem: how we can minimize rare-earth element use while still achieving high efficiency and compact motors. Another area we can focus on is new “gap” magnets. I have colleagues in materials science working at Ames National Laboratory to create these “gap” magnets (those that fall between expensive neodymium magnets and weaker ferrite magnets in both performance and cost). This will be a great opportunity to design new electric motors that use less or even no rare-earth elements.
Q: Is there a future in which we recover and reuse what we already have?
A: One option is to reuse the magnet as is and then put it in a new vehicle or new application. There’s significant interest from the U.S. government in that, because we are so dependent on these materials. For example, we can recycle electric and hybrid vehicle motors. In addition, many offshore wind turbines, for example, use neodymium-iron-boron magnets and are huge, heavy machines with enormous quantities of these rare earth elements. So, when they are decommissioned, one idea is to recover the magnets and repurpose them.
Another thing we have been preparing to work on is recycling magnets from permanent magnet motors. They are very strong, so the challenge is how do you remove them and how do you recycle them in large quantities? If we can replicate the process at scale and use it as a viable solution, then we, as a nation, will have more magnets. Extracting rare earth elements from magnets is a great opportunity to reduce reliance on foreign sources. And maybe, if we can get it to work, we will recycle magnets out of old cars in the same way we’re required to recycle 12-volt vehicle lead-acid batteries in most states. Right now, we’re just throwing magnets away. Similarly, we can recycle aluminum, copper and steel from motors. So, there is a whole opportunity out there for recycling motors.
Featured image caption: Electrical and Computer Engineering Professor Bulent Sarlioglu discusses electric motor research with a student in his laboratory. Sarlioglu’s group researches electric motors, which use rare earth elements. Credit: Joel Hallberg.