Spin Waves Revealed with X-Ray Vision

Spin Waves Revealed with X-Ray Vision
Christopher Crockett
Physics - Synopsis

Direct observation of coherent magnons with suboptical wavelengths in a single-crystalline ferrimagnetic insulator

J. Förster, J. Gräfe, J. Bailey, S. Finizio, N. Träger, F. Groß, S. Mayr, H. Stoll, C. Dubs, O. Surzhenko, N. Liebing, G. Woltersdorf, J. Raabe, M. Weigand, G. Schütz, and S. Wintz

Phys. Rev. B 100, 214416 (2019)

Schematics of the sample architecture and measurement setup. (a) Direct x-ray intensity image of the sample's transmission window. The central dark horizontal stripe is the antenna. (b) Single time frame of the time-resolved measurement with dynamical normalization that emphasizes the spin waves over the static background. Grayscale values represent the changes of the out-of-plane magnetization component. (c) Result of time-domain Fourier analysis, showing amplitude and phase of the waves in HSV (hue-saturation-value) color space (color code above the image).

Atomistic spin dynamics: Review

Atomistic spin dynamics and surface magnons.
Corina Etz, Lars Bergqvist, Anders Bergman, Andrea Taroni and Olle Eriksson
Journal of Physics: Condensed Matter 27, 243202 

 Bridging the gap: the ASD link between ab initio methods and micromagnetics simulations.

Magnon driven DW motion by DM

Magnon-Driven Domain-Wall Motion with the Dzyaloshinskii-Moriya Interaction.
Weiwei Wang, Maximilian Albert, Marijan Beg, Marc-Antonio Bisotti, Dmitri Chernyshenko, David Cortés-Ortuño, Ian Hawke, and Hans Fangohr
Phys. Rev. Lett. 114, 087203 (2015)

(a) Illustration of the head-to-head DW in the nanowire using red-blue opaque arrows. The translucent purple arrows represent a spin wave excitation. The DMI exerts a torque to change the DW tilt angle when spin waves pass through the DW. (b) DW profile using Eq. (5) with parameters A=8.78×10-12  J/m, K=1×105  J/m3, D=1.58×10-3  J/m2, K⊥=0 and Φ=0. The red dashed line shows the simulation data for mz with K⊥2=6×105  J/m3: the easy-plane anisotropy favors a reduced mz. (c) The dispersion relations inside and outside the DW

Magnon decays: a review

Spontaneous Magnon Decays.
M. E. Zhitomirsky, A. L. Chernyshev
ArXiv 1205.5278 (2012)

Zero-temperature self-energy diagrams due to the three-magnon, (a) and (b), and four-magnon, (c) and (d), interactions.

Thermoelectric effects in spintronics

Magnon-drag thermopile.
Marius V. Costache, German Bridoux, Ingmar Neumann, and Sergio O. Valenzuela
Nature Mater. 11, 199 (2012)

Magnon-drag detection principle and geometry of the device.

Magnon damping from DFT

Different dimensionality trends in the Landau damping of magnons in iron, cobalt, and nickel: Time-dependent density functional study.
Paweł Buczek, Arthur Ernst, and Leonid M. Sandratskii
Phys. Rev. B 84, 174418 (2011)

Spin waves of fcc Co. Solid circles correspond to ω0(q), while the error bars denote full width at  half maximum (FWHM) of the peak. Solid line denotes SW energies obtained from MFT. Solid triangles stand for the experimental estimation of the dispersion relation by Balash.

TM oxides by ab initio DFT calculations

Magnon spectrum of transition-metal oxides: Calculations including long-range magnetic interactions using the LSDA + U method.
F. Essenberger, S. Sharma, J. K. Dewhurst, C. Bersier, F. Cricchio, L. Nordström, and E. K. U. Gross
Phys. Rev. B 84, 174425 (2011)

N´eel temperatures as a function of U for NiO, CoO, and MnO. The dashed lines denote the experimental values and the gray solid lines are Monte Carlo simulations.

Manipulating magnetic DWs

Two articles showing diferent ways to interact with a domain wall have been published in the 8th July number of PRL:

1. Domain Wall Manipulation with a Magnetic Tip.
T. Stapelfeldt, R. Wieser, E.Y. Vedmedenko, and R. Wiesendanger
Phys. Rev. Lett. 107, 027203 (2011)

Spin currents by 3 magnon splitting

Controlled enhancement of spin-current emission by three-magnon splitting.
Hidekazu Kurebayashi, Oleksandr Dzyapko, Vladislav E. Demidov, Dong Fang, A. J. Ferguson
and Sergej O. Demokritov
Nature Mater. 10, 660 (2011)

Spin waves created by the three-magnon splitting measured
using BLS.

Spin transport through a DW

All-magnonic spin-transfer torque and domain wall propagation.
P. Yan, X. S. Wang, and X. R. Wang
Arxiv CondMat 1106.4382

Illustration of a transverse DW structure whose m is denoted by the (blue) arrows. The spin wave
(magnon) is a small amplitude precession of m (represented by the red cones) around the static DW.

Spin pumping by excited magnons

Spin Pumping by Parametrically Excited Exchange Magnons. 
C. W. Sandweg, Y. Kajiwara, A. V. Chumak, A. A. Serga, V. I. Vasyuchka, M. B. Jungfleisch, E. Saitoh, and B. Hillebrands
Phys. Rev. Lett. 106, 216601 (2011)

Viewpoint: Spin-magnon transmutation.
Gerrit E. Bauer, Yaroslav Tserkovnyak
Physics.4.40 (2011)

Generation of a magnon  by the spin-transfer torque.