RIKEN Researchers Uncover Direction-Dependent Electron Flow in Chiral Magnets

Researchers at RIKEN have made a significant breakthrough in understanding how electron flow is affected by direction in a specific type of magnet known as a chiral magnet. This discovery, published in the journal Science Advances on December 23, 2025, could pave the way for the development of low-energy electronic devices.

Chiral Magnets and Unique Electron Behavior

In conventional magnets, all electron spins align in the same direction. In contrast, chiral magnets exhibit a helical arrangement of electron spins, resembling a spiral staircase. This unique structure enables electrons to flow preferentially in one direction, similar to the behavior observed in diodes, but occurring within a single material instead of between two semiconductor junctions.

The potential applications of chiral magnets are substantial, particularly due to their ability to host tiny magnetic structures known as skyrmions. These skyrmions are seen as promising candidates for energy-efficient memory devices. While several theories have been proposed to explain the direction-dependent electron flow in these materials, no prior research had successfully isolated and identified the various mechanisms at play within a single chiral magnet.

New Findings and Implications for Future Research

To address this gap, Daisuke Nakamura and his team at the RIKEN Center for Emergent Matter Science have identified two distinct mechanisms governing the direction-dependent flow of electrons. The dominant mechanism varies based on environmental factors such as temperature and magnetic field strength. In certain scenarios, electrons moving in one direction encounter more scattering from magnetic quasiparticles with chirality, while those in the opposite direction experience less scattering.

The second mechanism involves the interaction between mobile electrons and the helical spins of static electrons, which contributes to the energy landscape affecting electron mobility within the chiral magnet.

Understanding these mechanisms proves challenging. The research team had to collaborate closely with theoretical physicists to complement their experimental measurements with necessary theoretical calculations. Nakamura remarked on the complexity of the task, saying, “Clarifying the mechanism is very challenging.”

The researchers focused on a chiral magnet composed of cobalt, zinc, and manganese. This particular combination allows for a helical spin arrangement across a broad temperature range, including room temperature, making it an ideal candidate for their investigations. The findings from this study may extend to other materials, suggesting a wide scope for future research into one-way electrical conduction.

Moving forward, the team plans to explore how variations in the ratios of the three metals in the chiral magnet affect electron flow, potentially unlocking new avenues for innovation in electronic materials.

For more information, refer to the paper by Daisuke Nakamura et al., titled “Nonreciprocal transport in a room-temperature chiral magnet,” published in Science Advances.