Efficient electromagnetic transducers for spin-wave devices

This paper presents a system-level efficiency analysis, a rapid design methodology, and a numerical demonstration of efficient sub-micron, spin-wave transducers in a microwave system. Applications such as Boolean spintronics, analog spin-wave-computing, and magnetic microwave circuits are expected to benefit from this analysis and design approach. These applications have the potential to provide a low-power, magnetic paradigm alternative to modern electronic systems, but they have been stymied by a limited understanding of the microwave, system-level design for spin-wave circuits. This paper proposes an end-to-end microwave/spin-wave system model that permits the use of classical microwave network analysis and matching theory towards analyzing and designing efficient transduction systems. This paper further compares magnetostatic-wave transducer theory to electromagnetic simulations and finds close agreement, indicating that the theory, despite simplifying assumptions, is useful for rapid yet accurate transducer design. It further suggests that the theory, when modified to include the exchange interaction, will also be useful to rapidly and accurately design transducers launching magnons at exchange wavelengths. Comparisons are made between microstrip and co-planar waveguide lines, which are expedient, narrowband, and low-efficiency transducers, and grating and meander lines that are capable of high-efficiency and wideband performance. The paper concludes that efficient microwave-to-spin-wave transducers are possible and presents a meander transducer design on YIG capable of launching $$\varvec{\lambda = 500}\,$$ λ = 500 nm spin waves with an efficiency of − 4.45 dB and a 3 dB-bandwidth of 134 MHz.

Efficient Electromagnetic Transducers For Spin-Wave Devices

This paper presents a system-level efficiency analysis, a rapid design methodology, and a numerical demonstration of efficient sub-micron, spin-wave transducers in a microwave system. Applications such as Boolean spintronics, analog spin-wave-computing, and magnetic microwave circuits are expected to benefit from this analysis and design approach. These applications have the potential to provide a low-power, magnetic paradigm alternative to modern electronic systems, but they have been stymied by a limited understanding of the microwave, system-level design for spin-wave circuits. This paper proposes an end-to-end microwave/spin-wave system model that permits the use of classical microwave network analysis and matching theory towards analyzing and designing efficient transduction systems. This paper further compares magnetostatic-wave transducer theory to electromagnetic simulations and finds close agreement, indicating that the theory, despite simplifying assumptions, is useful for rapid yet accurate transducer design. It further suggests that the theory, when modified to include the exchange interaction, will also be useful to rapidly and accurately design transducers launching magnons at exchange wavelengths. Comparisons are made between microstrip and co-planar waveguide lines, which are expedient, narrowband, and low-efficiency transducers, and grating and meander lines that are capable of high-efficiency and wideband performance. The paper concludes that efficient microwave-to-spin-wave transducers are possible and presents a meander transducer design on YIG capable of launching λ=500nm spin waves with an efficiency of -4.45 dB and a 3 dB-bandwidth of 134 MHz.

Управление свойствами спин-волнового транспорта в полукольцевом магнонном микроволноводе

Spin-wave transport along a waveguide structure with disturbed translational symmetry has been investigated. A semiring portion of a magnon microwaveguide has been made of a YIG film. It has been shown that one can control the dynamic magnetization spatial distribution by varying the magnetic biasing angle in the microwaveguide plane. Under such conditions, the transmission coefficient of standing waves changes noticeably. The structure suggested in this paper allows the rotation of spin-wave signals in an irregular configuration under the conditions of surface magnetostatic wave propagation. This effect may be used in planar magnon networks.

Функциональные блоки магнонных сетей на основе структур с нарушением трансляционной симметрии

We have studied the properties of spin-wave excitations in a structure that is a junction of two regular magnon waveguides. The proposed structure enables the transmission of spin-wave signals in an irregular structure in the propagation mode of a surface magnetostatic wave. Using the method of micromagnetic simulation, the characteristics of the wave process have been calculated when changing the structure parameters, magnitude and direction of a magnetization field. It is shown that a system with translational symmetry violation can be used to transmit a signal in three-dimensional configurations of magnon networks.

Anisotropy of magnetostatic wave group velocities in ferromagnetic waveguides

The results of theoretical and experimental study of anisotropic propagation of magnetostatic waves (MSW) in ferromagnetic thin-film microsize waveguides are presented. Electrodynamic model of tangentially magnetized ferromagnetic waveguide is developed. On the base of the model, the main features in rotation of group velocity vector of volume MSW (VMSW) by rotating a wave vector and a vector of an external bias magnetic field relative to the axis of symmetry of the waveguide are demonstrated. It is shown, that a decrease in a width of the waveguide to the micron size leads to non-reciprocal propagation of VMSW and to increase of angular divergence between the phase and group velocities of VMSW. The experimental research of T-shaped ferromagnetic microwaveguide demonstrates the difference in power levels of a signal that is branched in the shoulders of T-shaped waveguide when the bias magnetic field is rotated in the waveguide plane.

Dispersion characteristics of surface magnetostatic wave with dissipation

It is shown that the dispersion characteristics of spin surface waves with dissipation unlike undamped waves have the wave number maximum value at which there is a reversal in the dispersion curve of wavenumber downward. This forms the upper branch of the dispersion curve with the inverse dispersion and high attenuation, which gives rise to ambiguous depending on the frequency of the wave vector. Lower primary dispersion branch corresponds to waves with a direct dispersion, attenuation is proportional to the small parameter of dissipation. However, near the wave number maximum value the attenuation coefficient of the waves sharply increases. Some angular and frequency limits of the of surface wave propagation are changed as well.