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arXiv · 2109.05045

Electrical spectroscopy of the spin-wave dispersion and bistability in gallium-doped yttrium iron garnet

Joris J. Carmiggelt·Olaf C. Dreijer·Carsten Dubs·Oleksii Surzhenko·Toeno van der Sar
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Abstract

Yttrium iron garnet (YIG) is a magnetic insulator with record-low damping, allowing spin-wave transport over macroscopic distances. Doping YIG with gallium ions greatly reduces the demagnetizing field and introduces a perpendicular magnetic anisotropy, which leads to an isotropic spin-wave dispersion that facilitates spin-wave optics and spin-wave steering. Here, we characterize the dispersion of a gallium-doped YIG (Ga:YIG) thin film using electrical spectroscopy. We determine the magnetic anisotropy parameters from the ferromagnetic resonance frequency and use propagating spin wave spectroscopy in the Damon-Eshbach configuration to detect the small spin-wave magnetic fields of this ultrathin weak magnet over a wide range of wavevectors, enabling the extraction of the exchange constant $α=1.3(2)\times10^{-12}$ J/m. The frequencies of the spin waves shift with increasing drive power, which eventually leads to the foldover of the spin-wave modes. Our results shed light on isotropic spin-wave transport in Ga:YIG and highlight the potential of electrical spectroscopy to map out the dispersion and bistability of propagating spin waves in magnets with a low saturation magnetization.

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Joris J. Carmiggelt, Olaf C. Dreijer, Carsten Dubs, Oleksii Surzhenko, Toeno van der Sar. 2021-09-10. Electrical spectroscopy of the spin-wave dispersion and bistability in gallium-doped yttrium iron garnet. https://doi.org/10.1063/5.0070796

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