Experimentally determined correlation between direct and inverse Edelstein effects at Bi2O3/Cu interface by means of spin absorption method using lateral spin valve structure

Abstract: We have experimentally elucidated the correlation between inverse and direct Edelstein Effects (EEs) at Bi2O3/Cu interface by means of spin absorption method using lateral spin valve structure. The conversion coefficient {\lambda} for the inverse EE is determined by the electron momentum scattering time in the interface, whereas the coefficient q for the direct EE is by the spin ejection time from the interface. For the Bi2O3/Cu interface, the spin ejection time was estimated to be ~ 53 fs and the momentum scattering time ~ 13 fs at room temperature, both of which contribute to the total momentum relaxation time that defines the resistivity of the interface. The effective spin Hall angle for the Bi2O3/Cu interface amounts to ~ 10% which is comparable to commonly used spin Hall material such as platinum. Interesting to note is that the experimentally obtained Edelstein resistances given by the output voltage divided by the injection current for direct and inverse effects are the same. Analysis based on our phenomenological model reveals that the larger the momentum scattering time, the more efficient direct EE; and the smaller spin ejection time, the more efficient inverse EE.