Bachelor's Thesis
Dispersion relation of magnonic crystals with nontrivial spatial distribution of magnetic anisotropy
Final Thesis 6.82 MBAuthor of thesis: Ing. Ondřej Wojewoda, Ph.D.
Acad. year: 2017/2018
Supervisor: Ing. Lukáš Flajšman, Ph.D.
Reviewer: Mgr. Jaroslav Hamrle, Ph.D.
Abstract:Magnonics is a novel field of research dealing with the physics of spin waves, which are collective excitations of a magnetization. Magnonic crystals, the basic building blocks of magnonic circuits, allow extended control over the spin-wave dispersion. The periodic structure of magnonic crystals results in the formation of a complex band structure with a gap of forbidden frequencies. Periodic structures are conventionally prepared by a local modulation of material thickness or by a step change of saturation magnetization. The presented work deals with the theoretical verification of dispersion relations of magnonic crystals, where the periodicity of the system is achieved by the modulation of the direction of uniaxial magnetic anisotropy and by continuous change of saturation magnetization. For a better insight into the propagation of spin waves in a material with non-homogeneous magnetic properties, a theory describing the refraction and reflection of spin waves at the interface is presented and further verified by numerical simulations.
Spin waves, magnonics, analytical modeling, micromagnetic simulation, Snell’s law, magnonic crystal, dispersion relation, Damon-Eshbach mode
Date of defence
22.06.2018
Result of the defence
Defended (thesis was successfully defended)
Grading
A
Process of defence
Byly zodpovězeny otázky oponenta.
Language of thesis
Czech
Faculty
Department
Study programme
Applied Sciences in Engineering (B3A-P)
Field of study
Physical Engineering and Nanotechnology (B-FIN)
Composition of Committee
prof. RNDr. Tomáš Šikola, CSc. (předseda)
prof. RNDr. Miroslav Liška, DrSc. (místopředseda)
prof. RNDr. Bohumila Lencová, CSc. (člen)
prof. RNDr. Petr Dub, CSc. (člen)
prof. RNDr. Radim Chmelík, Ph.D. (člen)
prof. RNDr. Jiří Spousta, Ph.D. (člen)
doc. Ing. Radek Kalousek, Ph.D. (člen)
prof. RNDr. Pavel Zemánek, Ph.D. (člen)
RNDr. Antonín Fejfar, CSc. (člen)
doc. Ing. Stanislav Průša, Ph.D. (člen)
Supervisor’s report
Ing. Lukáš Flajšman, Ph.D.
Grade proposed by supervisor: A
Reviewer’s report
Mgr. Jaroslav Hamrle, Ph.D.
Grade proposed by reviewer: A