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Title: Spin waves in micro-structured yttrium iron garnet nanometer-thick films

Abstract

We investigated the spin-wave propagation in a micro-structured yttrium iron garnet waveguide of 40 nm thickness. Utilizing spatially-resolved Brillouin light scattering microscopy, an exponential decay of the spin-wave amplitude of (10.06 ± 0.83) μm was observed. This leads to an estimated Gilbert damping constant of α=(8.79±0.73)×10{sup −4}, which is larger than damping values obtained through ferromagnetic resonance measurements in unstructured films. The theoretically calculated spatial interference of waveguide modes was compared to the spin-wave pattern observed experimentally by means of Brillouin light scattering spectroscopy.

Authors:
; ; ; ; ; ;  [1]; ;  [2]; ;  [3]
  1. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
  2. Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)
  3. Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208 (United States)
Publication Date:
OSTI Identifier:
22410062
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION SPECTROSCOPY; BRILLOUIN EFFECT; COMPARATIVE EVALUATIONS; DAMPING; FERRITE GARNETS; FERROMAGNETIC RESONANCE; FILMS; INTERFERENCE; LIGHT SCATTERING; MICROSCOPY; SPIN WAVES; WAVE PROPAGATION; WAVEGUIDES; YTTRIUM COMPOUNDS

Citation Formats

Jungfleisch, Matthias B., E-mail: jungfleisch@anl.gov, Zhang, Wei, Jiang, Wanjun, Wu, Stephen M., Pearson, John E., Bhattacharya, Anand, Hoffmann, Axel, Chang, Houchen, Wu, Mingzhong, Sklenar, Joseph, and Ketterson, John B. Spin waves in micro-structured yttrium iron garnet nanometer-thick films. United States: N. p., 2015. Web. doi:10.1063/1.4916027.
Jungfleisch, Matthias B., E-mail: jungfleisch@anl.gov, Zhang, Wei, Jiang, Wanjun, Wu, Stephen M., Pearson, John E., Bhattacharya, Anand, Hoffmann, Axel, Chang, Houchen, Wu, Mingzhong, Sklenar, Joseph, & Ketterson, John B. Spin waves in micro-structured yttrium iron garnet nanometer-thick films. United States. doi:10.1063/1.4916027.
Jungfleisch, Matthias B., E-mail: jungfleisch@anl.gov, Zhang, Wei, Jiang, Wanjun, Wu, Stephen M., Pearson, John E., Bhattacharya, Anand, Hoffmann, Axel, Chang, Houchen, Wu, Mingzhong, Sklenar, Joseph, and Ketterson, John B. Thu . "Spin waves in micro-structured yttrium iron garnet nanometer-thick films". United States. doi:10.1063/1.4916027.
@article{osti_22410062,
title = {Spin waves in micro-structured yttrium iron garnet nanometer-thick films},
author = {Jungfleisch, Matthias B., E-mail: jungfleisch@anl.gov and Zhang, Wei and Jiang, Wanjun and Wu, Stephen M. and Pearson, John E. and Bhattacharya, Anand and Hoffmann, Axel and Chang, Houchen and Wu, Mingzhong and Sklenar, Joseph and Ketterson, John B.},
abstractNote = {We investigated the spin-wave propagation in a micro-structured yttrium iron garnet waveguide of 40 nm thickness. Utilizing spatially-resolved Brillouin light scattering microscopy, an exponential decay of the spin-wave amplitude of (10.06 ± 0.83) μm was observed. This leads to an estimated Gilbert damping constant of α=(8.79±0.73)×10{sup −4}, which is larger than damping values obtained through ferromagnetic resonance measurements in unstructured films. The theoretically calculated spatial interference of waveguide modes was compared to the spin-wave pattern observed experimentally by means of Brillouin light scattering spectroscopy.},
doi = {10.1063/1.4916027},
journal = {Journal of Applied Physics},
number = 17,
volume = 117,
place = {United States},
year = {Thu May 07 00:00:00 EDT 2015},
month = {Thu May 07 00:00:00 EDT 2015}
}
  • Here, we investigated the spin-wave propagation in a micro-structured yttrium iron garnet waveguide of 40 nm thickness. Utilizing spatially-resolved Brillouin light scattering microscopy, an exponential decay of the spinwave amplitude of 10 μm was observed. This leads to an estimated Gilbert damping constant of α = (8.79 ± 0.73) x 10 $-$4, which is larger than damping values obtained through ferromagnetic resonance measurements in unstructured films. Furthermore, we compared the theoretically calculated spatial interference of waveguide modes to the spin-wave pattern observed experimentally by means of Brillouin light scattering spectroscopy.
  • Nanometer (nm)-thick yttrium iron garnet (Y{sub 3}Fe{sub 5}O{sub 12}, YIG) films present interest for spintronics. This work employs spectral ellipsometry and magneto-optic Kerr effect (MOKE) spectra to characterize nm-thick YIG films grown on single-crystal Gd{sub 3}Ga{sub 5}O{sub 12} substrates by magnetron sputtering. The thickness (t) of the films ranges between 10 nm and 40 nm. Independent on t, the polar MOKE hysteresis loops saturate in the field of about 1.8 kOe, consistent with the saturation magnetization in bulk YIG (4πM{sub s} ≈ 1.75 kG). The MOKE spectrum measured at photon energies between 1.3 eV and 4.5 eV on the 38-nm-thick film agrees with that measured on single-crystalmore » YIG bulk materials. The MOKE spectrum of the 12-nm-thick film still preserves the structure of the bulk YIG but its amplitude at lower photon energies is modified due to the fact that the radiation penetration depth exceeds 20 nm. The t dependence of the MOKE amplitude is consistent with MOKE calculations. The results indicate that the films are stoichiometric, strain free, without Fe{sup 2+}, and preserve bulk YIG properties down to t ≈ 10 nm.« less
  • Yttrium iron garnet (YIG) films that are in the nanometer thickness range and show extremely low damping are reported. The films were deposited via sputtering at room temperature and were then annealed in O 2 at high temperature. A 22-nm-thick YIG film showed a Gilbert damping constant α = (8.58 ± 0.21) × 10 -5, which represents the lowest damping ever reported for nanometer-thick magnetic films. The film had a gyromagnetic ratio of |γ| = 2.83 MHz/Oe and a saturation induction of 4πM s = 1766 G, which are both very close to those of single-crystal YIG bulk materials. Themore » film had a very smooth surface, with an rms surface roughness of about 0.13 nm.« less