Spinwave dispersion curves for yttrium iron garnet

The full magnon spectrum of yttrium iron garnet

“…The inclusion of interactions up to the 6th nearest neighbour is guided by previous experimental results and ab initio calculations which indicate that the magnitudes of J 4 -J 6 could be as much as 5-10% that of the dominant exchange interaction J 1 . 21,23 Due to the extremely large number (20) of magnetic atoms within the primitive cell, and the consideration of so many exchange pathways, this analysis would be impossible without the use of sophisticated software such as SpinW as the construction of an analytic model would be prohibitively time consuming. During the fitting process, features in the spectrum were weighted so that weak but meaningful features in the data were considered as significant as strong features.…”

“…Despite this, surprisingly little data exists relating to the detail of its magnon mode structure. The previous key work in this area is due to Plant et al, 20,21 35-45 years ago. Using a triple-axis spectrometer, these early neutron scattering measurements were able to record a few of the spin wave modes up to approximately 55 meV (14 THz), but crucially there are a total of 20 distinct modes for a given wave vector and they are predicted to extend up to approximately 90 meV (22 THz).…”

Spin Seebeck effect and ballistic transport of quasi-acoustic magnons in room-temperature yttrium iron garnet films

“…This velocity can be calculated using experimental [31,32] and theoretical [33][34][35][36][37] data of the magnon spectra in YIG. It is known, that starting from about 1 THz (≈20 K) and up to the end of the first Brillouin zone at about 6.5 THz (≈300 K), the lowest magnon branch, which is mostly populated at room temperature, has an almost linear dispersion relation ω(k).…”

Magnon Spintronics

“…The magnetic moment of the loop is m ¼ ids (6) where ds is the elemental area of size pr 2 enclosed by the current i = q e v e /2pr. The direction of ds is determined by the direction of conventional current so that Eq.…”

“…As well as their obvious role in enriching our understanding of fundamental magnetics, the subtle magnetic-field dependent dynamics of such waveguide systems opens doors to the experimental exploration of certain general aspects of wave and quasi-particle dynamics not readily observable in other physical domains. In a single magnetic sample, spin waves can be observed over a frequency range from roughly one gigahertz to several terahertz, and a range of wavelengths which spans a remarkable seven orders of magnitude (nanometres to centimeters) [6].…”