Figure 1: Schematic of the device, showing the TI Bi2Se3 placed between two different FM layers. The surface state is indicated by the small up- and down-arrows, showing counter-propagating spin-momentum locked conduction. The precession of magnetisation excited around the static bias field drives a pure spin current from the CoFe layer through the TI Bi2Se3 into the NiFe layer, exerting a spin transfer torque.
Figure 2: Band structure of a TI, showing the valence (blue) and conduction (orange) bands, with the spin-locked surface states crossing the bulk band gap.
Figure 3: (a) Illustration of the experimental configuration for the measurement of time resolved (TR) XMCD. The magnetisation of the stack about the applied field Hbias is driven by the radiofrequency field, HRF. (b) TR-XMCD results for NiFe continuously driven at 4 GHz for the CoFe(30)/Bi2Se3(8)/NiFe(30) sample (thicknesses in nm). Varying static bias field is indicated by colour of lines, offset for clarity, showing increase in amplitude and phase shift across resonance at a field of 14 mT.
To discuss potential applications for BLADE (beamline I10), please contact Principal Beamline Scientist Dr Paul Steadman: firstname.lastname@example.org.For more information on the Magnetic Spectroscopy Group, please contact group leader Professor Gerrit van der Laan: email@example.com.
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