Magnetic asymmetry around the 3p absorption edge in Fe and Ni

• This work is a joint theoretical and experimental study of the relation between the magneto- optical response of a material in the sub-picosecond timescale and its instantaneous magnetisation. We perform pump-probe experiments in the transverse magneto-optical Kerr effect (T-MOKE) geometry. We measure the magnetic asymmetry of elemental Fe and Ni before and after the laser pulse. The observed differences between the magnetic asymmetry curves for various photon energies suggest that the relation between asymmetry and sample magnetization is more complex than a simple proportionality. Further insight is obtained by means of theoretical simulations based on density-functional theory. Our calculations show that non-linear effects in the asymmetry are most prominent at energies corresponding to the absorption edge and that the proportionality is recovered outside of this region. In conclusion, our experimental and theoretical results emphasize the need of including the complex relation between asymmetry and magnetization in the interpretation of ultrafast magnetization experiments in terms of microscopic properties. 

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

T-MOKE

ultrafast magnetization dynamics

Fe

iron

Ni

nikkel

Fysik

Physics

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)