Chapter 7
Current-Induced Dynamics of Chiral
Magnetic Structures: Creation, Motion,
and Applications
Jan Masell and Karin Everschor-Sitte
Abstract Magnetic textures can be manipulated by electric currents via the mechanisms of spin-transfer and spin-orbit-torques. We review how these torques can be
exploited to create chiral magnetic textures in magnets with broken inversion symmetries, including domain walls and skyrmions. These chiral textures can also be
moved by (electric) currents and obey very rich dynamics. For example, magnetic
domain walls feature the famous Walker breakdown, and magnetic whirls are subject to the skyrmion Hall effect, which is rooted in their real-space topology. These
properties led to a variety of potential novel applications which we briefly overview.
7.1 Introduction
Magnetic materials have been studied over the centuries for various prospects, in
particular yielding the fundamental building blocks in computers that enable us to
store tremendous amounts of data and transcending our culture to the age of information technology. Permanent magnetism as a key feature in these devices which
offers not only fundamentally interesting, but also application-wise impressive and
practical phenomena. The fact that magnets can be strongly influenced by external
magnetic fields is both, a blessing and a curse. On the one hand, localized magnetic fields can be used to easily manipulate magnetic states of matter. On the other
hand, magnetic devices are sensitive to invasive, external stimuli. Even nowadays,
where magnetic mass storages in the form of rotating hard disc drives are steadily
replaced by all-electric devices, magnetic recording media still appears throughout
our everyday lives. Besides their intrinsic advantage of being non-volatile, magnetic
recording media have to overcome some challenges such as increasing the speed
J. Masell
RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
e-mail: jan.masell@riken.jp
K. Everschor-Sitte (B)
Johannes Gutenberg University, Institute of Physics, Staudingerweg 7, 55128 Mainz, Germany
e-mail: kaeversc@uni-mainz.de
© Springer Nature Switzerland AG 2021
E. Kamenetskii (ed.), Chirality, Magnetism and Magnetoelectricity,
Topics in Applied Physics 138,
https://doi.org/10.1007/978-3-030-62844-4_7
147
Current-Induced Dynamics of Chiral
Magnetic Structures: Creation, Motion,
and Applications
Jan Masell and Karin Everschor-Sitte
Abstract Magnetic textures can be manipulated by electric currents via the mechanisms of spin-transfer and spin-orbit-torques. We review how these torques can be
exploited to create chiral magnetic textures in magnets with broken inversion symmetries, including domain walls and skyrmions. These chiral textures can also be
moved by (electric) currents and obey very rich dynamics. For example, magnetic
domain walls feature the famous Walker breakdown, and magnetic whirls are subject to the skyrmion Hall effect, which is rooted in their real-space topology. These
properties led to a variety of potential novel applications which we briefly overview.
7.1 Introduction
Magnetic materials have been studied over the centuries for various prospects, in
particular yielding the fundamental building blocks in computers that enable us to
store tremendous amounts of data and transcending our culture to the age of information technology. Permanent magnetism as a key feature in these devices which
offers not only fundamentally interesting, but also application-wise impressive and
practical phenomena. The fact that magnets can be strongly influenced by external
magnetic fields is both, a blessing and a curse. On the one hand, localized magnetic fields can be used to easily manipulate magnetic states of matter. On the other
hand, magnetic devices are sensitive to invasive, external stimuli. Even nowadays,
where magnetic mass storages in the form of rotating hard disc drives are steadily
replaced by all-electric devices, magnetic recording media still appears throughout
our everyday lives. Besides their intrinsic advantage of being non-volatile, magnetic
recording media have to overcome some challenges such as increasing the speed
J. Masell
RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
e-mail: jan.masell@riken.jp
K. Everschor-Sitte (B)
Johannes Gutenberg University, Institute of Physics, Staudingerweg 7, 55128 Mainz, Germany
e-mail: kaeversc@uni-mainz.de
© Springer Nature Switzerland AG 2021
E. Kamenetskii (ed.), Chirality, Magnetism and Magnetoelectricity,
Topics in Applied Physics 138,
https://doi.org/10.1007/978-3-030-62844-4_7
147