Study of resistive switching, photoresponse, and magnetism modulation in the Pt/Co3O4/Nb:SrTiO3 heterostructure

Co3O4 thin films are epitaxially grown on an Nb-doped (001) SrTiO3 (NSTO) single-crystal substrate using pulsed laser deposition to form Pt/Co3O4/NSTO heterostructures. These devices display stable bipolar resistive switching (RS) with multilevel memory, good endurance, and a maximum ON/OFF ratio of up to 104. The high resistance state of the device exhibits significant photoresponse characteristics with an open-circuit voltage of 0.47 V, under the illumination of a 405 nm laser. Moreover, the saturation magnetization of the Co3O4 film shows reversible switching associated with different resistance states. The RS and related photoelectricity could be attributed to the modulation of the potential barrier via the oxygen vacancy migration coupled with electron trapping/detrapping and light illumination at the Co3O4/NSTO interface; meanwhile, the change in magnetism might be due to the redistribution of the oxygen vacancies. These results provide a promising pathway for developing multifunctional, multilevel memory devices with RS, photoresponse, and magnetism.