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PhD defence Qiao Li: 'Recording electronic and magnetic dynamics at a trillionth of a second' (Uitreiking)

Date
Tuesday 7 September 2021Add to my calendar
Time
from 16:30
Location
Academiezaal Aula, Comeniuslaan 2
Speaker
Qiao Li, MSc.
Description

Promotors: prof. Theo Rasing & prof. Alexey Kimel

In magnetic multilayer thin films, ultrashort laser excitation can effectively generate sub-picosecond spin dynamics and charge currents which results in THz emission. Using THz emission spectroscopy as an ultrafast contactless ammeter we study the THz emissivity in Co/Pt. Moreover, THz emission can be used as a probe to study the laser-induced first-order magnetic phase transition in FeRh/Pt and FeRh/Au where a latency between the initial laser excitation and the emergence of a net magnetization was observed. Finally, in Tb/Co ferrimagnet multilayers, we demonstrate the ability to switch the magnetization direction with a single laser pulse, known as single shot all optical switching. The all optical switching was confirmed as well in a Tb/Co based magnetic tunnel junction electrode after annealing at 250 degrees Celsius, represented the first initial steps towards the development of spintronic photonic hybrid magnetic memory devices.