Antiferromagnets could be better than ferromagnets for some ultrafast, high-density memories

Good news!

"While antiferromagnets show much promise for spintronics applications, they have proved more difficult to control compared to ferromagnets. Researchers in Japan have now succeeded in switching an antiferromagnetic manganese–tin nanodot using electric current pulses as short as 0.1 ns. Their work shows that these materials can be used to make efficient high-speed, high-density, memories that operate at gigahertz frequencies, so outperforming ferromagnets in this range. ..."

"Advances in spintronics have led to the practical use of magnetoresistive random-access memory (MRAM), a non-volatile memory technology that supports energy-efficient semiconductor integrated circuits. Recently, antiferromagnets─magnetic materials with no net magnetization─have attracted growing attention as promising complements to conventional ferromagnets. While their properties have been extensively studied, clear demonstrations of their technological advantages have remained elusive.

Now, researchers ... have provided the first compelling evidence of the unique benefits of antiferromagnets. Their study shows that antiferromagnets enable high-speed, high-efficiency memory operations in the gigahertz range, outperforming their ferromagnetic counterparts. ..."

From the editor's summary and abstract:

"Editor’s summary

Antiferromagnetic spintronics hold the promise of high speed and high efficiency unachievable with ferromagnets. However, reaching these goals in experiments has proven tricky. Takeuchi et al. realized all-electrical driving of an antiferromagnetic Mn3Sn (manganese-tin) nanodot. The researchers used electric-current pulses as short as 0.1 nanoseconds at current densities insensitive to pulse width. ...

Abstract

Electric current driving of antiferromagnetic states at radio or higher frequencies remains challenging to achieve. In this study, we report all-electrical, gigahertz-range coherent driving of chiral antiferromagnet manganese-tin (Mn3Sn) nanodot samples. High coherence in multiple trials and threshold current insensitive to pulse width, in contrast to results observed with ferromagnets, were achieved in subnanosecond range, allowing 1000/1000 switching by 0.1-nanosecond pulses at zero field. These features are attributed to the inertial nature of antiferromagnetic excitations. Our study highlights the potential of antiferromagnetic spintronics to combine high speed and high efficiency in magnetic device operations."

Antiferromagnets could be better than ferromagnets for some ultrafast, high-density memories – Physics World

Antiferromagnets Outperform Ferromagnets in Ultrafast, Energy-Efficient Memory Operations (original news release)

Electrical coherent driving of chiral antiferromagnet (no public access)

(a) Schematic illustration of memory device consisting of chiral antiferromagnet Mn3Sn / nonmagnetic metal heterostructure (b) A scanning electron microscope image of the fabricated device with Mn3Sn nanodot and nonmagnetic metal channel. ©Yutaro Takeuchi et al.