Disparate ultrafast dynamics of itinerant and localized magnetic moments in gadolinium metal.
The Heisenberg-Dirac intra-atomic exchange coupling is responsible for the formation of the atomic spin moment and thus the strongest interaction in magnetism. Therefore, it is generally assumed that intra-atomic exchange leads to a quasi-instantaneous aligning process in the magnetic moment dynamics of spins in separate, on-site atomic orbitals. Following ultrashort optical excitation of gadolinium metal, we concurrently record in photoemission the 4f magnetic linear dichroism and 5d exchange splitting. Their dynamics differ by one order of magnitude, with decay constants of 14 versus 0.8 ps, respectively. Spin dynamics simulations based on an orbital-resolved Heisenberg Hamiltonian combined with first-principles calculations explain the particular dynamics of 5d and 4f spin moments well, and corroborate that the 5d exchange splitting traces closely the 5d spin-moment dynamics. Thus gadolinium shows disparate dynamics of the localized 4f and the itinerant 5d spin moments, demonstrating a breakdown of their intra-atomic exchange alignment on a picosecond timescale.
Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.|Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany.
B
B
Frietsch
Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.|Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany.
J
J
Bowlan
Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.|Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany.
R
R
Carley
Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.|Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany.
M
M
Teichmann
Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany.
S
S
Wienholdt
Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany.
D
D
Hinzke
Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany.
U
U
Nowak
Department of Physics and Astronomy, Uppsala University, PO Box 516, 75120 Uppsala, Sweden.|Charles University, Faculty of Mathematics and Physics, DCMP, Ke Karlovu 5, CZ-12116 Prague 2, Czech Republic.
K
K
Carva
Department of Physics and Astronomy, Uppsala University, PO Box 516, 75120 Uppsala, Sweden.
P M
PM
Oppeneer
Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
M
M
Weinelt