scholarly journals Direct observation of multiband transport in magnonic Penrose quasicrystals via broadband and phase-resolved spectroscopy

2021 ◽  
Vol 7 (35) ◽  
pp. eabg3771
Author(s):  
Sho Watanabe ◽  
Vinayak S. Bhat ◽  
Korbinian Baumgaertl ◽  
Mohammad Hamdi ◽  
Dirk Grundler

Quasicrystals are aperiodically ordered structures with unconventional rotational symmetry. Their peculiar features have been explored in photonics to engineer bandgaps for light waves. Magnons (spin waves) are collective spin excitations in magnetically ordered materials enabling non–charge-based information transmission in nanoscale devices. Here, we report on a two-dimensional magnonic quasicrystal formed by aperiodically arranged nanotroughs in ferrimagnetic yttrium iron garnet. By phase-resolved spin wave imaging at gigahertz frequencies, multidirectional emission from a microwave antenna is evidenced, allowing for a quasicontinuous radial magnon distribution, not observed in reference measurements on a periodic magnonic crystal. We observe partial forbidden gaps, which are consistent with analytical calculations and indicate band formation as well as a modified magnon density of states due to backfolding at pseudo-Brillouin zone boundaries. The findings promise as-desired filters and magnonic waveguides reaching out in a multitude of directions of the aperiodic lattice.

2012 ◽  
Vol 190 ◽  
pp. 373-376
Author(s):  
M. Mansurova ◽  
O.V. Kolokoltsev

In this work we present a new concept for measuring high intensity pulsed magnetic fields (h (t)) through the spectral analysis of spin excitations in a saturated yttrium-iron garnet (YIG) thin film grown on a gadolinium gallium garnet (GGG) substrate. The spectrum of spin excitations, generated in the sample by picosecond h (t), was determined with the help of a magnetooptical (MO) Faraday probe in the guided wave regime of lightwave propagation. This technique, compared to the standard MO cells, allows one to avoid saturation effects because the amplitude of h (t) is measured in the frequency domain, and allows us to realize the analysis in real time taking advantage of strong a MO signal.


Author(s):  
J.Y. Laval

The exsolution of magnetite from a substituted Yttrium Iron Garnet, containing an iron excess may lead to a transitional event. This event is characterized hy the formation of a transitional zone at the center of which the magnetite nucleates (Fig.1). Since there is a contrast between the matrix and these zones and since selected area diffraction does not show any difference between those zones and the matrix in the reciprocal lattice, it is of interest to analyze the structure of the transitional zones.By using simultaneously different techniques in electron microscopy, (oscillating crystal method microdiffraction and X-ray microanalysis)one may resolve the ionic process corresponding to the transitional event and image this event subsequently by high resolution technique.


1997 ◽  
Vol 07 (C1) ◽  
pp. C1-283-C1-286
Author(s):  
P. Novák ◽  
J. Englich ◽  
H. Stepánková ◽  
J. Kohout ◽  
H. Lütgemeier ◽  
...  

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-200-C1-201 ◽  
Author(s):  
P. HANSEN ◽  
W. TOLKSDORF

JETP Letters ◽  
1996 ◽  
Vol 64 (3) ◽  
pp. 171-176 ◽  
Author(s):  
B. A. Kalinikos ◽  
N. G. Kovshikov ◽  
M. P. Kostylev ◽  
H. Benner

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1554
Author(s):  
Justinas Januskevicius ◽  
Zivile Stankeviciute ◽  
Dalis Baltrunas ◽  
Kęstutis Mažeika ◽  
Aldona Beganskiene ◽  
...  

In this study, an aqueous sol-gel synthesis method and subsequent dip-coating technique were applied for the preparation of yttrium iron garnet (YIG), yttrium iron perovskite (YIP), and terbium iron perovskite (TIP) bulk and thin films. The monophasic highly crystalline different iron ferrite powders have been synthesized using this simple aqueous sol-gel process displaying the suitability of the method. In the next step, the same sol-gel solution was used for the fabrication of coatings on monocrystalline silicon (100) using a dip-coating procedure. This resulted, likely due to substrate surface influence, in all coatings having mixed phases of both garnet and perovskite. Thermogravimetric (TG) analysis of the precursor gels was carried out. All the samples were investigated by X-ray powder diffraction (XRD) analysis. The coatings were also investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Mössbauer spectroscopy. Magnetic measurements were also carried out.


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