Epitaxial Strain and Ferroelectric Field-effect Modulation of Magnetotransport in Correlated Oxide Thin Films

Ferroelectric field-effect approach has been adopted by synthesizing Pb(ZrxTi1-x)O 3 (PZT)/SNNO and PZT/SIO heterostructures. Working with a prototype ferroelectric field-effect transistor, we have demonstrated robust resistance switching up to 75% and nonvolatile modulation of T MI for PZT/SNNO grown on LaAlO3 substrate. However, the PZT hardly has any effect on the SNNO for the case of STO. In both systems, we also observed a pronounced relaxation of off state resistance, showing a thermally activated behavior. The time dynamics and thermal response of the retention behavior suggest that strain-induced oxygen vacancies play a critical role in the ferroelectric field-effect instability. Meanwhile, we have also demonstrated a resistance modulation of 25% at 300 K in PZT/SNNO heterostructures. In addition, using the polarization field of PZT, we have demonstrated tunable spin relaxation. This suggests that the ferroelectric field-effect approach is a promising route to realize spintronics devices, such as the spin field-effect transistor.