Magnetic anisotropy and GGG substrate stray field in YIG films down to millikelvin temperatures.

Autor: Serha RO; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.; Vienna Doctoral School in Physics, University of Vienna, 1090 Vienna, Austria., Voronov AA; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.; Vienna Doctoral School in Physics, University of Vienna, 1090 Vienna, Austria., Schmoll D; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.; Vienna Doctoral School in Physics, University of Vienna, 1090 Vienna, Austria., Verba R; Institute of Magnetism, Kyiv, 03142 Ukraine., Levchenko KO; Faculty of Physics, University of Vienna, 1090 Vienna, Austria., Koraltan S; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.; Vienna Doctoral School in Physics, University of Vienna, 1090 Vienna, Austria.; Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria., Davídková K; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.; Vienna Doctoral School in Physics, University of Vienna, 1090 Vienna, Austria., Budinská B; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.; Vienna Doctoral School in Physics, University of Vienna, 1090 Vienna, Austria., Wang Q; Huazhong University of Science and Technology, Wuhan, China., Dobrovolskiy OV; Faculty of Physics, University of Vienna, 1090 Vienna, Austria., Urbánek M; CEITEC BUT, Brno University of Technology, 61200 Brno, Czech Republic., Lindner M; INNOVENT e.V. Technologieentwicklung, 07745 Jena, Germany., Reimann T; INNOVENT e.V. Technologieentwicklung, 07745 Jena, Germany., Dubs C; INNOVENT e.V. Technologieentwicklung, 07745 Jena, Germany., Gonzalez-Ballestero C; Institute for Theoretical Physics, Vienna University of Technology, 1040 Vienna, Austria., Abert C; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.; Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria., Suess D; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.; Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria., Bozhko DA; Department of Physics and Energy Science, University of Colorado Colorado Springs, Colorado Springs, CO 80918 USA., Knauer S; Faculty of Physics, University of Vienna, 1090 Vienna, Austria., Chumak AV; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.
Jazyk: angličtina
Zdroj: Npj spintronics [Npj Spintron] 2024; Vol. 2 (1), pp. 29. Date of Electronic Publication: 2024 Jul 02.
DOI: 10.1038/s44306-024-00030-7
Abstrakt: Quantum magnonics investigates the quantum-mechanical properties of magnons, such as quantum coherence or entanglement for solid-state quantum information technologies at the nanoscale. The most promising material for quantum magnonics is the ferrimagnetic yttrium iron garnet (YIG), which hosts magnons with the longest lifetimes. YIG films of the highest quality are grown on a paramagnetic gadolinium gallium garnet (GGG) substrate. The literature has reported that ferromagnetic resonance (FMR) frequencies of YIG/GGG decrease at temperatures below 50 K despite the increase in YIG magnetization. We investigated a 97 nm-thick YIG film grown on 500 μm-thick GGG substrate through a series of experiments conducted at temperatures as low as 30 mK, and using both analytical and numerical methods. Our findings suggest that the primary factor contributing to the FMR frequency shift is the stray magnetic field created by the partially magnetized GGG substrate. This stray field is antiparallel to the applied external field and is highly inhomogeneous, reaching up to 40 mT in the center of the sample. At temperatures below 500 mK, the GGG field exhibits a saturation that cannot be described by the standard Brillouin function for a paramagnet. Including the calculated GGG field in the analysis of the FMR frequency versus temperature dependence allowed the determination of the cubic and uniaxial anisotropies. We find that the total crystallographic anisotropy increases more than three times with the decrease in temperature down to 2 K. Our findings enable accurate predictions of the YIG/GGG magnetic systems behavior at low and ultralow millikelvin temperatures, crucial for developing quantum magnonic devices.
Competing Interests: Competing interestsThe authors declare no competing interests.
(© The Author(s) 2024.)
Databáze: MEDLINE
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