Thermally Enhanced Dual-Mode Resistive Switching via Interfacial Strain Engineering in SmNiO₃/PMN-PT Heterostructures

SmNiO₃ thin films on PMN-PT ferroelectric substrates enable electrically switchable strain engineering, an advantage over permanently fixed lattice-mismatch strain. However, strain-engineered resistive switching in SmNiO₃ via ferroelectric substrates remains largely unexplored. Here, by stabilizing high-quality epitaxial SmNiO₃ films on (011)-cut PMN-PT through a LaAlO₃/SrTiO₃ graded buffer interface, we demonstrate dual-mode resistive modulation in SmNiO₃/PMN-PT heterostructures: reversible butterfly-shaped hysteresis under bipolar fields arising from dynamic electrostrain, and nonvolatile switching through non-180° ferroelastic domain reorientation. Moderate heating to 75 °C boosts the resistance modulation, correlated with enhanced strain output from the PMN-PT substrate near its phase transition. At the same bias of 12 kV/cm, the modulation increases from -6.4% at 25 °C to -11.9%; even at only 6 kV/cm, the modulation reaches -6.7%, exceeding the room-temperature value at 12 kV/cm. These results demonstrate the potential of SmNiO₃/PMN-PT heterostructures for dual-mode resistive switching, integrating both volatile and nonvolatile modulation within a single material system through a thermally enhanced strain-coupling mechanism. This work serves as a proof-of-concept demonstration for future exploration in neuromorphic applications.