A research team led by Professor Jung-Il Hong from the Department of Physics and Chemistry at DGIST has successfully used short bursts of electric current to modify the internal spin structure of a type of magnetic material called a ferrimagnet. This change lowered the material's "compensation temperature"—the point at which opposing magnetic fields cancel each other—by as much as 110 degrees Kelvin. The findings, published in the journal Advanced Functional Materials, suggest a new way to control magnetic properties using only electrical signals, without altering the material's composition or thickness. This could lead to advancements in spintronic memory devices, which rely on the spin of electrons rather than their charge for data storage. Ferrimagnets are materials where two types of magnetization exist in opposite directions. As temperature changes, the strength of these magnetizations also changes. At the compensation temperature, the two magnetic fields are equal in magnitude but opposite in direction, effectively canceling each other out. This temperature is crucial for controlling magnetization, especially for high-speed and high-density memory technologies. Traditionally, adjusting the compensation temperature required changes to the material’s composition, thickness, or additional processing steps like heating or ion implantation. These methods are not ideal for fine-tuning magnetic properties after a device is built, as they can alter the material’s structure or composition. The research team used a technique called "spin-orbit torque," which involves passing an electric current through a multilayer thin film made of platinum (Pt), iridium manganese (IrMn₃), and cobalt-gadolinium (CoGd). The current alters the spin configuration in the IrMn₃ layer, which in turn influences the spin state of the neighboring CoGd layer. This change in spin configuration modifies the compensation temperature of the material without altering its composition. In experiments, the compensation temperature of a Co₀.₅Gd₀.₅ thin film dropped by about 70 K, while that of a Co₀.₆₈Gd₀.₃₂ thin film decreased by up to 110 K. These changes were achieved simply by adjusting the strength and duration of the current pulses. Professor Jung-Il Hong noted that the study shows how the magnetic properties of a material can be influenced not just by the types and arrangement of its atoms, but also by the configuration of its internal spins. Because the compensation temperature can be precisely adjusted using current pulses, this method offers a promising path for developing next-generation spintronic memory devices. These devices could have location-specific magnetic properties, allowing for more efficient and flexible data storage solutions. The ability to control magnetic behavior with electricity, rather than chemical or structural changes, opens new possibilities for designing advanced electronic components.