Voltage-tunable magnetism achieved in stacked 2D layers at room temperature

Researchers have created a van der Waals heterostructure that exhibits multiferroic behavior at room temperature, combining ferromagnetic and ferroelectric orders. The material allows magnetic properties to be controlled with small voltages, which could enable low-power memory and spintronic devices. The work was published in Science and addresses the challenge of achieving stable 2D multiferroics under thermal fluctuations.

The researchers fabricated the heterostructure by mechanically exfoliating thin flakes from bulk crystals of Fe₃GaTe₂ and CuInP₂S₆, then stacking them vertically. Transparent indium tin oxide and chromium-gold electrodes were deposited to apply voltages across the device. This design separates the ferromagnetic and ferroelectric orders into distinct layers, circumventing the difficulty of combining multiple ferroic orders within a single-phase material.

The work addresses a fundamental obstacle: thermal fluctuations at room temperature typically destabilize long-range ferroic ordering in two-dimensional systems. By demonstrating stable multiferroicity in a stacked configuration, the team showed that voltage-induced changes in the ferroelectric layer can couple to the magnetic layer, enabling electrical control of magnetism. This coupling is the essential mechanism for future magnetoelectric devices.