  The inverse Rashba-Edelstein effect (IREE) is a spin conversion mechanism
that recently attracts attention in spintronics and condensed matter physics.
In this letter, we report an investigation of the IREE in Bi/Ag by using
ferrimagnetic insulator yttrium iron garnet (YIG). We prepared two types of
samples with opposite directions of the Rashba field by changing a stacking
order of Bi and Ag. An electric current generated by the IREE was observed from
both stacks, and an efficiency of spin conversion -characterized by the IREE
length- was estimated by taking into account a number of contributions left out
in previous studies. This study provides a further insight into the IREE spin
conversion mechanism: important step towards achieving efficient spin-charge
conversion devices.
