Magnetic circular dichroism in two-photon photoemission.
We report the observation of magnetic circular dichroism (MCD) in two-photon photoemission (2PPE). The Heusler alloys Ni2MnGa and Co2FeSi were investigated by excitation with femtosecond laser light, showing MCD asymmetries of A=(3.5+/-0.5)x10;{-3} for Ni2MnGa and of A=(2.1+/-1.0)x10;{-3} for Co2FeSi, respectively. A theoretical explanation is provided based on local spin-density calculations for the magnetic dichroic response; the computed 2PPE MCD agrees well with the experiment. The observed 2PPE magnetic contrast represents an interesting alternative for future time-resolved photoemission studies on surface magnetism practicable in the laboratory.
Hild
K
K
Institut für Physik, Staudinger Weg 7, Universität Mainz, D-55128 Mainz, Germany.
Maul
J
J
Schönhense
G
G
Elmers
H J
HJ
Amft
M
M
Oppeneer
P M
PM