Inertial spin dynamics : the role of magneto-crystalline anisotropy

• We investigate the spin dynamics driven by terahertz magnetic fields in epitaxial thin films of cobalt in its three crystalline phases with distinct magneto-crystalline anisotropy. The terahertz magnetic field generates a torque on the magnetization which causes it to precess for about 1 ps, with a sub-picosecond temporal lag from the driving force. Then, the magnetization undergoes natural damped oscillations in the THz range at a characteristic frequency of the crystalline phase, containing higher-order harmonics of the fundamental. We describe the experimental observations solving the inertial Landau-Lifshitz-Gilbert equation. Using the results from the relativistic theory of magnetic inertia, we find that the angular momentum relaxation time η is the only material parameter needed to describe all the experimental evidence. Our experiments suggest a correlation between η and the strength of the magneto-crystalline anisotropy

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

Terahertz

Inertial dynamics

nutation

higher-harmonics

magneto-crystalline anisotropy

cobalt

fysik

Physics

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)