All optical method research of ultrafast spin dynmics

1
All optical method research of ultrafast spin
dynmics by Time resolved magneto-optical Kerr
effect system Yi Ming Department of
Physics, Fudan University, Shanghai 200433, China
Experiment
Abstract The surface magneto-optic Kerr effect
(SMOKE) has greatly impacted research on magnetic
thin films, due to its experimental simplicity,
high sensitivity and local probe property for in
situ measurement. It become more easy to research
ultrafast process of magnetic materials with the
help of fs-laser system and pump-probe technique.
The longitudinal Time resolved magneto-optic Kerr
effect system had been built to measure the
ultrafast dynamics process of in-plane magnetized
materials. We using the Tri-temprature model to
study the relaxation of electron, spin and
lattice.
COHERENT Auto-Model lock Ti Sapphire
Femtosecond Laser system Regenerative Amplifier
Pulse Energy 3mJ Rep. Rate1kHz
Pulse Duration50fs
Three temperature Model
30nm-thick Co2FeAl0.5Si0.5(CFAS)/MgO(20nm) on
MgO(001) single crystal Sample-1 in-situ
annealing 480C 1hour sample-2 in-situ
annealing 540C 1hour
From the results we found that the
ferromagnetical samples of different spin
polarization showed similar electron-spin
relaxation but different spin-lattice relaxation
tes2.320.12ps tsl409.5326.17ps
Demagnetization
tes2.061.47ps tsl637.2117.21ps