A team of scientists at the Lawrence Berkeley National Laboratory has discovered a new material that is both liquid and magnetic. The team’s process uses iron oxide and 3D printing techniques to transform semimagnetic liquids into permanent magnets.

The discovery was an unexpected accomplishment, according to the leader of the team’s study, Thomas Russell, who also serves as a visiting faculty scientist at Berkeley Lab and a professor of polymer science and engineering at the University of Massachusetts, Amherst.

Russell’s team first stumbled upon the idea of liquid magnets while investigating how to stabilize liquids with iron oxide nanoparticles.

“We were not looking for liquid magnets,” Russell said in an email. “This occurred serendipitously when we used some iron oxide particles and saw droplets rotating on a magnetic stirring plate.”

According to a press release from Berkeley Lab, Russell’s team injected the droplets of iron oxide-infused water into an oil using a modified 3D printer. When placed near a solid magnetic coil, the droplets turned into magnets. When the solid magnetic coil was taken away, the droplets gravitated toward each other in unison, suggesting that they had become permanently magnetic.

Russell said in an email that his team members did not know what they had discovered until they devised a series of “proof-of-principle experiments.” After completing additional quantitative measurements using a magnetometer, a device that measures the strength and direction of a magnetic field, in collaboration with scientists at Berkeley Lab, their suspicions were confirmed, Russell said.

“The … liquid droplets behave similarly to solid magnets, but retain the liquid characteristics,” Russell said in an email. “(These magnetic droplets) represent a milestone for the further development of the magnetic materials.”

Because of their soft, reconfigurable and spatially conforming structure, liquid magnets offer new opportunities for research and application. Russell believes that liquid magnets will eventually be used to facilitate the development of advanced instruments and new material theories, gaining relevance in the fields of physics, biology and chemistry.

Specifically, Russell said liquid magnets can be used for a variety of flexible electronics, including magnetically actuated liquid robots that would be able to adapt to their environments. Other potential applications include liquid vessels for active matter and programmable liquid droplet patterns. According to the press release, liquid magnets could even be used to create 3D-printed artificial cells that deliver targeted cancer therapies. 

Regardless of how liquid magnets are eventually applied, Russell said he is excited about the prospects that the discovery promises.

“This is a magnetic phenomenon that people who work with solid magnets just don’t think about. We’re still trying to arrive at a fundamental understanding of this,” Russell said. “The thing that really excites me the most is that … (liquid magnets) are opening up a new area of science, in terms of magnetism.”