FORC-Diagram Analysis for a Step-like Magnetization Reversal in Nanopatterned Stripe Array

The fabrication approach of a magnonic crystal with a step-like hysteresis behavior based on a uniform non-monotonous iron layer made by shadow deposition on a preconfigured substrate is reported. The origin of the step-like hysteresis loop behavior is studied with local and integral magnetometry methods, including First-Order Reversal Curves (FORC) diagram analysis, accompanied with magnetic microstructure dynamics measurements. The results are validated with macroscopic magnetic properties and micromagnetic simulations using the intrinsic switching field distribution model. The proposed fabrication method can be used to produce magnonic structures with the controllable hysteresis plateau region’s field position and width that can be used to control the magnonic crystal’s band structure by changing of an external magnetic field.

Magnonic Crystal with Strips of Magnetic Nanoparticles: Modeling and Experimental Realization via a Dip-Coating Technique

In this article, we describe a magnonic crystal formed by magnetite nanoparticles. The periodic strip-like structure of the nanoparticles was fabricated on the surface of thin yttrium iron garnet single-crystal film grown on a gallium–gadolinium garnet substrate via dip-coating techniques. It was shown that such periodic structure induces the formation of the bandgaps in the transmission spectra of magnetostatic surface spin-waves (MSSW). The structure was simulated by the transfer matrix method. Spin-wave detection has been carried out by using a pair of microwave antennas and a vector network analyzer.

Recursive evolution of spin-wave multiplets in magnonic crystals of antidot-lattice fractals

We explored spin-wave multiplets excited in a different type of magnonic crystal composed of ferromagnetic antidot-lattice fractals, by means of micromagnetic simulations with a periodic boundary condition. The modeling of antidot-lattice fractals was designed with a series of self-similar antidot-lattices in an integer Hausdorff dimension. As the iteration level increased, multiple splits of the edge and center modes of quantized spin-waves in the antidot-lattices were excited due to the fractals’ inhomogeneous and asymmetric internal magnetic fields. It was found that a recursive development (Fn = Fn−1 + Gn−1) of geometrical fractals gives rise to the same recursive evolution of spin-wave multiplets.

Magnonic Crystal with Strips of Magnetic Nanoparticles: Modeling and Experimental Realization via a Dip-coating Technique

In this article, we show theoretically and experimentally the formation of spin-waves band gaps in a magnonic crystal that was implemented by the deposition of periodic micro-structured strips of magnetite nanoparticles. A theoretical model describing the spectra of the transmitted spin-waves bandgaps is proposed. This is achieved using a simple model based on microwave transmission line theory and considering the presence of micro-structured strips of magnetite nanoparticles on the surface. Such magnonic crystal of equally spaced micro-structured strips of magnetite nanoparticles on the surface of an yttrium iron garnet thin film has been implemented and measured. The periodic micro-structured nanoparticles are deposited on the surface of such yttrium iron garnet single-crystal film grown on a gallium-gadolinium garnet substrate via dip-coating technique. Propagation of magnetostatic surface spin-waves is studied and it is shown that the presence of such periodic structure leads to the formation of spin-wave band gaps in the transmission characteristics. The spin-wave detection has been carried out using a pair of microwave antennas and a vector network analyzer. The results show that the periodic structure formed by the magnetite strips modifies the spectra of the transmitted spin waves producing band gaps.