Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Mechanism of femtosecond laser induced ultrafast demagnetization in ultrathin film magnetic multilayers

Pan, S.; Ganss, F.; Panda, S.; Sellge, G.; Banerjee, C.; Sinha, J.; Hellwig, O.; Barman, A.

Ever since its discovery ultrafast demagnetization has remained one of the most
intriguing research areas in magnetism. Here, we demonstrate that in [Co (tCo )/
Pd (0.9 nm)] 8 multilayers, the characteristic decay time in femtosecond time-
scale varies non-monotonically with tCo in the range 0.07 nm B tCo B 0.75 nm.
Further investigation reveals higher spin fluctuation at higher ratio of electron to
Curie temperature to be responsible for this. Microscopic three-temperature
modelling unravels a similar trend in the spin–lattice interaction strength, which
strongly supports our experimental observation. The knowledge of the fem-
tosecond magnetization decay mechanism in ultrathin ferromagnetic films is
unique and important for the advancement of fundamental magnetism besides
their potential applications in ultrahigh speed spintronic devices.

Publ.-Id: 34448