Effect of O₂ post annealing and plasma treatment in enhancing the resistance switching characteristics of Pr_0.7Ca _0.3MnO₃ films with SrRuO₃ buffer layers

Pr_0.7Ca_0.3MnO₃ (PCMO) films with SrRuO₃ (SRO) buffer layers were deposited on Pt/Ti/SiO ₂/Si(100) substrates at various substrate temperatures ranging from 300 °C to 700 °C by rf-magnetron sputtering. The PCMO films were found to be crystallized at increasing substrate temperature. The electroresistance (ER) ratio of the Au/SRO/PCMO/SRO/Pt sandwich structure was enhanced by improvement of the grain size in the PCMO films. Prom X-ray photoelectron microscopy (XPS) measurements after oxygen post annealing, we found that an excess of oxygen caused by the post annealing of the PCMO films led to an increase in the Mn⁴⁺/Mn³⁺ ratio at the PCMO surface, resulting in an increased ER ratio. The Au/SRO/PCMO/SRO/Pt structure, which was grown at a substrate temperature of 700 °C, showed the largest ER ratio of 5840 % after oxygen annealing at 600 °C. As a result of surface treatment by using an oxygen plasma through the interface of the Au/SRO/PCMO/SRO/Pt sandwich structure, the reproducible property of these structures was improved.