  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.
