Onset of spin wave time-domain fractals in a dynamic artificial crystal

Journal article

We report on the first observation of an exact fractal pattern in the time-domain arising spontaneously from adynamic artificial crystal (DAC). The all-magnon process occurs in a passive, unlithographed magnetic wave-guide. The DAC was created by a standing spin wave of frequency ƒ_DAC in a region of nonlinear waveguide, resulting in a spatio-temporally periodic potential. The interaction of travelling spin waves of frequency ƒ′ with the DAC resulted in a series of new modes appearing in a comb with intervals Δƒ⁽⁰⁾ = | ƒ_DAC − ƒ′|. As the magnetic field H was increased a 1st pre-fractal pattern was observed with frequency interval Δƒ⁽¹⁾ = Δƒ⁽⁰⁾/2. Finally, the onset of a 2nd pre-fractal was observed with frequency interval Δƒ⁽²⁾ = Δƒ⁽¹⁾/2 = Δƒ⁽⁰⁾/4. The magnetic field dependence of the nonlinear signals matched that of the DAC. The spin wave fractal behavior was demonstrated for different values of ƒ′.

Authors: Inglis, A; Gregg, J

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Journal of Magnetism and Magnetic Materials
• Volume: 495
• Article number: 165868
• Publication date: 2019-09-18
• Acceptance date: 2019-09-16
• DOI: 10.1016/j.jmmm.2019.165868
• ISSN: 0304-8853
• Language: English