New magnetizable shape memory alloy with low energy loss

June 17, 2023

Researchers at Tohoku University have achieved a significant breakthrough in shape memory alloys (SMAs) by developing a palladium-based metamagnetic shape memory alloy (MMSMA) with reduced energy loss. SMAs are materials that can return to their original shape after being heated or cooled, but their response rate is limited by the need for heating or cooling. MMSMAs, a type of SMA, can undergo phase transformation when exposed to a magnetic field, improving their response time.

However, MMSMAs have traditionally suffered from high energy loss during phase transformation, particularly at low temperatures. The new Pd MMSMA developed by the research group exhibits significantly lower energy loss, around 1/100th compared to existing MMSMAs, even at low temperatures of approximately 100 K. This breakthrough could open up new possibilities for the use of MMSMAs in various applications where low energy loss and rapid response are critical.

“We were astonished at the small energy loss in our new Pd-based alloy. Thus, our study also sought to answer two questions. How does the energy loss behave when the temperature lowers even further, such as at the liquid-helium temperature (4.2 K), and why did our material exhibit such a small energy loss?” said Xiao Xu, corresponding author of the paper and assistant professor at Tohoku University's Graduate School of Engineering.

To do so, Xu and his colleagues at Tohoku University’s Institute for Materials Research (IMR) teamed up with the University of Tokyo’s Institute for Solid State Physics (ISSP). They first conducted magnetization measurements by using pulsed high magnetic fields at liquid-helium temperature. Much like previous SMAs, the newly developed Pd-based SMA also demonstrated an increase in energy loss as the temperature dropped. But the energy loss was still significantly smaller than current SMAs.