Date: Tuesday, January 28, 2014
Time: 11:00 am
Speaker: Dr. Ales Hrabec, Leeds University, UK
Title: DMI meter: Dzyaloshinskii-Moriya interaction in Pt/Co/Ir films
Location: 67-3111 Chemla Room
The Dzyaloshinskii-Moriya interaction (DMI) can be measured via several techniques but the magnetic field-based method avoids all the problems with patterning and potential mixing with current-related effects such as the Spin Hall Effect or the Rashba field. It has been suggested that the observation of Walker breakdown would be a direct measure of the DM constant D. However, this is extremely difficult experimentally as the Walker breakdown is hidden in the creep regime or not even experimentally reachable. In our experimental work we show that we are able to measure the constant D even in the creep regime which is experimentally very easy to achieve. To demonstrate this technique we grow multilayers of Ta(3 nm)/Pt(5 nm)/Co(0.8 nm)/Ir(t)Pt(3.5 nm) where t is varied from 0 nm up to 1.3 nm. The choice of Pt/Co and Co/Ir interfaces is motivated by the fact that one would expect the opposite DMI contribution, therefore the Co film should experience higher effective DMI from the two DMI active layers. By using Kerr microscopy we show that we are able to control the DW structure and its chirality.