  The electrochemical switching of SrCoOx-based non-volatile memory with
thin-film-transistor structure was examined by using liquid-leakage-free
electrolytes with different conductivity (s) as the gate insulator. We first
examined leakage-free water, which is incorporated in the amorphous (a-) 12CaO
7Al2O3 film with nanoporous structure (CAN), but the electrochemical
oxidation/reduction of SrCoOx layer required the application of high gate
voltage (Vg) up to 20 V for a very long retention-time (t) 40 minutes,
primarily due to the low s (2.0 x 10-8 S cm-1 at RT) of leakage-free water.We
then controlled the s of leakage-free electrolyte, infiltrated in the a-NaxTaO3
film with nanopillar array structure, from 8.0 x 10-8 S cm-1 to 2.5 x 10-6 S
cm-1 at RT by changing the x = 0.01-1.0. As the result, the t, required for the
metallization of SrCoOx layer under small Vg = -3 V, becomes two orders of
magnitude shorter with increase of the s of the a-NaxTaO3 leakage-free
electrolyte. These results indicate that the ion migration in the leakage-free
electrolyte is the rate-determining step for the electrochemical switching,
compared to the other electrochemical process, and the high s of the
leakage-free electrolyte is the key factor for the development of the
non-volatile SrCoOx-based electro-magnetic phase switching device.
