Tohoku University switches nonlinear Hall signal in Mn3Sn film with current pulses at room temperature
Researchers at Tohoku University and JAEA reversed the sign of a third-order nonlinear Hall response in a chiral antiferromagnet film using spin-orbit torque. The work is a laboratory demonstration.
Researchers at Tohoku University and the Japan Atomic Energy Agency (JAEA) used electric current to switch a quantum-geometric nonlinear Hall (QgNLH) state in an epitaxial thin film of the chiral antiferromagnet Mn3Sn. The results were published in the journal Newton on 4 November 2026. According to the release, this is the first control of such a state by electric current sciencedirect.com
Newtonsciencedirect.comOpen source ↗. The experiments were carried out at room temperature.
Nonlinear Hall response in Mn3Sn
In an ordinary conductor, voltage and current are proportional, as described by Ohm's law and the Hall effect. In the nonlinear Hall effect, the Hall voltage in the direction transverse to the current no longer follows this linear relation. Quantum geometry, the geometric structure of electronic quantum states, plays a role in producing such a response.
The team observed a third-order nonlinear Hall effect in the Mn3Sn film at room temperature, in which the nonlinear voltage is proportional to the cube of the current. The sign of the effect flips when the chiral spin structure is reversed, and the flip is non-volatile. Combining experiments with theoretical calculations, the authors concluded that the effect has a quantum-geometric origin.
Switching by spin-orbit torque
When current flows in a heavy-metal layer adjacent to Mn3Sn, the resulting spin-orbit torque acts on the spin structure of Mn3Sn and can switch it. By applying current pulses of opposite polarity, the researchers switched the sign of the third-order nonlinear Hall response sciencedirect.com
Newtonsciencedirect.comOpen source ↗.
Lead author Tomohiro Uchimura reported that deterministic switching of the QgNLH state was achieved under a finite bias magnetic field, while at zero bias field the state fluctuated. The authors note that quantum geometry has been regarded as a built-in property of a material. Here the response was changed by electrically controlling the magnetic order.
Corresponding authors Jiahao Han and Shunsuke Fukami said the approach may help develop current-tunable nonlinear devices such as frequency multiplexers and rectifiers. They also expect such devices to benefit from the energy efficiency and speed that magnetoresistive random access memory (MRAM) has gained from spintronic methods. The reported work consists of thin-film experiments.
