Anisotropic spin waves in two-dimensional triangular shaped bi-component magnonic crystal

• Published in: Journal of magnetism and magnetic materials 2019-11, Vol.490, p.165484, Article 165484
• Main Authors: Choudhury, Samiran, Pan, Santanu, Barman, Saswati, Otani, YoshiChika, Barman, Anjan
• Format: Article
• Language: English
• Subjects: Active control; Anisotropy; Bi-component magnonic crystal; Bias; Communications systems; Constituents; Crystals; Dipoles; Electronic devices; Kerr magnetooptical effect; Lattice vibration; Magnetic fields; Magnetic measurement; Magnons; Micromagnetic simulation; Microwave communications; Shape dependence; Shape effects; Spatial distribution; Spin dynamics; Spin waves; Spintronics; Time-resolved magneto-optical Kerr effect magnetometry
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2019.165484

•Fabrication of 2D triangle shaped bicomponent magnonic crystal and investigation of their magnetization dynamics by time-resolved magneto-optical Kerr effect.•Observation of six- and four-fold rotational symmetries in configurational anisotropy.•Observation of mode conversion from extended to quantized spin waves.•An improved spin wave propagation velocity in 2D triangle shaped BMC is proposed. Bi-component magnonic crystals with a strong dipole-exchange interaction across the interface of the constituent magnetic elements have shown promising potentials in magnonics and magnon-spintronics. Here, we have reported an all-optical investigation of spin wave dynamics in an array of periodically arranged bi-component magnonic crystal in the form of triangular shaped Ni80Fe20 nanoelements embedded in Co50Fe50 matrix using time-resolved magneto-optical Kerr effect magnetometry. The spin wave spectra obtained from the sample reveal a broad band of spin wave modes where they possess a strong and systematic bias magnetic field tunability which is crucial for active control over such system in device applications. Further, the spin wave modes show a six-fold and a four-fold rotational anisotropy with the bias field orientation due to combined effects of element shape and lattice symmetry. Micromagnetic simulations reproduce the experimental results qualitatively where the simulated mode profiles unravel the spatial distribution of spin wave frequencies inside both constituent elements while the internal magnetic fields play a crucial role for the observed tunability of spin wave dynamics. Development of such magnetically coupled embedded magnetic nanostructures can pave a new pathway in designing the future magnonic devices and faster microwave communication systems.