Chapter 8
Microwave-Driven Dynamics of
Magnetic Skyrmions Under a Tilted
Magnetic Field: Magnetic Resonances,
Translational Motions, and Spin-Motive
Forces
Masahito Mochizuki
Abstract Magnetic skyrmions, particle-like magnetic textures characterized by a
quantized topological invariant in magnets with broken spatial inversion symmetry, are currently attracting enormous research interest in the field of spintronics.
Recent intensive studies have uncovered that magnetic skyrmions exhibit rich physical phenomena and device functions originating from their topological nature. In
this chapter, we discuss microwave-induced dynamical phenomena of magnetic
skyrmions associated with their peculiar spin-wave modes. In particular, we focus
on a situation that the magnetic skyrmions are confined in a quasi-two-dimensional
thin-plate magnet under application of a static magnetic field tilted from the perpendicular direction. It is theoretically demonstrated that the spin-wave excitations of
these magnetic skyrmions by microwave irradiation give rise to translational motion
of the skyrmions and generation of the DC electric voltages. These phenomena
indicate that rich physics and functionalities are hidden in the microwave-driven
skyrmion dynamics under a tilted magnetic field.
8.1 Introduction
Magnetic skyrmions, topological magnetic entities carrying a quantized topological
invariant in magnets without spatial inversion symmetry, are currently attracting a
great deal of research interest [1–7]. In the early 1960s, an English theoretical physicist, Tony Hilton Royle Skyrme, proposed a theoretical concept of Skyrmion as a
soliton solution of the nonlinear sigma model to account for the stability of hadron
in the nuclear physics [8, 9]. This originally proposed skyrmion is a hedgehoglike particle composed of field vectors pointing in every direction wrapping a sphere
M. Mochizuki (B)
Department of Applied Physics, Waseda University, 3-4-1 Okubo, Shinjuku-ku,
Tokyo 169-8555, Japan
e-mail: masa_mochizuki@waseda.jp
© 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_8
183
Microwave-Driven Dynamics of
Magnetic Skyrmions Under a Tilted
Magnetic Field: Magnetic Resonances,
Translational Motions, and Spin-Motive
Forces
Masahito Mochizuki
Abstract Magnetic skyrmions, particle-like magnetic textures characterized by a
quantized topological invariant in magnets with broken spatial inversion symmetry, are currently attracting enormous research interest in the field of spintronics.
Recent intensive studies have uncovered that magnetic skyrmions exhibit rich physical phenomena and device functions originating from their topological nature. In
this chapter, we discuss microwave-induced dynamical phenomena of magnetic
skyrmions associated with their peculiar spin-wave modes. In particular, we focus
on a situation that the magnetic skyrmions are confined in a quasi-two-dimensional
thin-plate magnet under application of a static magnetic field tilted from the perpendicular direction. It is theoretically demonstrated that the spin-wave excitations of
these magnetic skyrmions by microwave irradiation give rise to translational motion
of the skyrmions and generation of the DC electric voltages. These phenomena
indicate that rich physics and functionalities are hidden in the microwave-driven
skyrmion dynamics under a tilted magnetic field.
8.1 Introduction
Magnetic skyrmions, topological magnetic entities carrying a quantized topological
invariant in magnets without spatial inversion symmetry, are currently attracting a
great deal of research interest [1–7]. In the early 1960s, an English theoretical physicist, Tony Hilton Royle Skyrme, proposed a theoretical concept of Skyrmion as a
soliton solution of the nonlinear sigma model to account for the stability of hadron
in the nuclear physics [8, 9]. This originally proposed skyrmion is a hedgehoglike particle composed of field vectors pointing in every direction wrapping a sphere
M. Mochizuki (B)
Department of Applied Physics, Waseda University, 3-4-1 Okubo, Shinjuku-ku,
Tokyo 169-8555, Japan
e-mail: masa_mochizuki@waseda.jp
© 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_8
183