Spintronics technology holds the potential to propel the development of high - speed, low - power storage - computation chips. It offers a fresh avenue to break through the limitations of the von Neumann architecture and cater to the computational requirements of the post - Moore era. Devices in the third generation of spintronics generate spin - orbit torques via spin currents, which in turn enable the manipulation of magnetic bits.

For an extended period, the academic community has held the belief that spin - orbit torques stem from spin currents directly produced by effects like the spin Hall effect. Meanwhile, orbital angular momentum, owing to its high degree of localization, was thought to be incapable of interacting with magnetic bits. Nevertheless, recent studies have put forward a hypothesis. They suggest that orbital angular momentum can give rise to non - local orbital currents. Through spin - orbit coupling at the interface of magnetic materials, these non - local orbital currents are transformed into spin currents, which then exert powerful spin - orbit torques. This hypothesis has ignited a debate within the spintronics field, emerging as a scientific issue that demands urgent resolution.

Recently, a research team from the Institute of Semiconductors at the Chinese Academy of Sciences conducted experiments on non - magnetic conductor/ferromagnetic bilayers. Their findings revealed that the orbital Hall effect of Ta is unable to generate non - local orbital currents that participate in the spin - orbit torque effect. Moreover, they discovered that the spin Hall effect is the sole source of spin - orbit torques in Ta heterojunctions. This study clears up the controversy surrounding the orbital Hall effect of Ta and serves as a valuable reference for researching orbital current effects in other systems.