Spin-Wave Modes in Transition from a Thin Film to a Full Magnonic Crystal

Abstract

Spin-wave modes are studied under the gradual transition from a flat thin film to a 'full' (one-dimensional) magnonic crystal. For this purpose, the surface of a pre-patterned 36.8 nm thin permalloy film was sequentially ion milled resulting in magnonic hybrid structures, referred to as surface-modulated magnonic crystals, with increasing modulation depth. After each etching step, ferromagnetic resonance measurements were performed yielding the spin-wave resonance modes in backward-volume and Damon-Eshbach geometry. The spin-wave spectra of these hybrid systems reveal an even larger variety of spin-wave states compared to the 'full' magnonic crystal. The measurements are corroborated by quasi-analytical theory and micromagnetic simulations in order to study the changing spin-wave mode character employing spin-wave mode profiles. In backward-volume geometry, a gradual transition from the uniform mode in the film limit to a fundamental mode in the thin part of the magnonic crystal was observed. Equivalently, the first and the second film modes are transform into a center and an edge mode of the thick part of the magnonic crystal. Simple transition rules from the $n^{\mathrm{th}}$ film mode to the $m^{\mathrm{th}}$ mode in the 'full' magnonic crystal are formulated unraveling the complex mode structure particularly in the backward-volume geometry. An analogous analysis was performed in the Damon-Eshbach geometry.

References in corpus (11)

• Realization of XNOR and NAND spin-wave logic gates
• Scattering of backward spin waves in a one-dimensional magnonic crystal
• Current-controlled dynamic magnonic crystal
• Design of a spin-wave majority gate employing mode selection
• Scattering of surface and volume spin waves in a magnonic crystal
• Voltage-Controlled Nano-Scale Reconfigurable Magnonic Crystal
• Design and optimization of one-dimensional ferrite-film based magnonic crystals
• The role of the internal demagnetizing field in a surface-modulated magnonic crystal
• Symmetry and localization properties of defect modes in magnonic superlattices
• Spin wave surface states in one-dimensional planar magnonic crystals
• Magnetization dynamics in magnonic structures with different geometries: interfaces, notches and waveguides

Cited by in corpus (11)

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• Nonreciprocal surface magnetoelastic dynamics
• Reversible tuning of omnidirectional band gaps in two-dimensional magnonic crystals by magnetic field and in-plane squeezing
• Imaging non-standing spin-waves in confined micron-sized ferromagnetic structures under uniform excitation
• Controlling the propagation of dipole-exchange spin waves using local inhomogeneity of the anisotropy
• Nonstanding spin waves in a single rectangular permalloy microstrip under uniform magnetic excitation
• Tunable magnonic crystal in a hybrid superconductor--ferrimagnet nanostructure
• Magnetodynamic properties of dipole-coupled 1D magnonic crystals
• Transition magnon modes in thin ferromagnetic nanogratings
• Pulse-driven depinning of magnetic gap modes in ferromagnetic films
• Engineering Magnetic Anisotropy in Permalloy Films via Atomic Force Nanolithography