The remanent magnetization of ferromagnets has been extensively studied and utilized for binary information storage. Initially, magnetic memory designs relied on magnetization switching via locally generated magnetic fields. However, pivotal insights in condensed matter physics later suggested the feasibility of electrical means for this purpose. In the 1990s, Slonczewski and Berger introduced the concept of current-induced spin torques in magnetic multilayers, enabling a spin-polarized current from one ferromagnet to switch the magnetization of another. This breakthrough led to the development of spin-transfer-torque magnetic random-access memories (MRAMs). Recent fundamental research has uncovered other current-induced torques, such as spin-orbit torques (SOTs), paving the way for next-generation devices like SOT MRAMs and skyrmion-based devices. Simultaneously, multiferroics and their magnetoelectric coupling, initially explored in the 1960s, experienced a resurgence. Numerous multiferroic compounds with novel magnetoelectric coupling mechanisms were discovered, and high-quality multiferroic films, notably BiFeO3, were synthesized. This resurgence also inspired novel device concepts for information and communication technology, such as the magnetoelectric spin-orbit (MESO) transistor. The evolution of electrical magnetization switching is a synergy between fundamental research (in spintronics, condensed matter physics, and materials science) and technology (MRAMs, MESO transistors, etc.). This synergy has led to significant scientific and technological breakthroughs, including the conceptualization of pure spin currents, the observation of magnetic skyrmions, and the discovery of spin-charge interconversion effects. Consequently, this field has not only integrated MRAMs into consumer electronics but also advanced research in related areas like ferroelectrics and magnonics. This article just out in Reviews of Modern Physics covers recent advances in controlling magnetism through electric fields and current-induced torques. It begins with fundamental concepts in these two directions, discusses their combination, and addresses various families of devices utilizing electrical control of magnetic properties across different application fields. Finally, the review provides perspectives on emerging fundamental physics concepts and new directions in materials science.
We hope this paper will serve as a useful reference for all scientists of the field for several years to come. We expect it will also guide our community towards the technological integration of the concepts presented.
Albert Fert, Ramamoorthy Ramesh, Vincent Garcia, Fèlix Casanova, Manuel Bibes
Electrical control of magnetism by electric field and current-induced torques
Rev. Mod. Phys. 96, 015005 (2024) [pdf]