Observation of coherent helimagnons and gilbert damping in an itinerant magnet.
We study the magnetic excitations of itinerant helimagnets by applying time-resolved optical spectroscopy to Fe(0.8)Co(0.2)Si. Optically excited oscillations of the magnetization in the helical state are found to disperse to lower frequency as the applied magnetic field is increased; the fingerprint of collective modes unique to helimagnets, known as helimagnons. The use of time-resolved spectroscopy allows us to address the fundamental magnetic relaxation processes by directly measuring the Gilbert damping, revealing the versatility of spin dynamics in chiral magnets.
Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. jdkoralek@lbl.gov
J D
JD
Koralek
D
D
Meier
J P
JP
Hinton
A
A
Bauer
S A
SA
Parameswaran
A
A
Vishwanath
R
R
Ramesh
R W
RW
Schoenlein
C
C
Pfleiderer
J
J
Orenstein