Defect chemical differences between the changes of resistive states at room temperature and at elevated temperatures were investigated. Here we use the temperature change to switch between two regimes in which oxygen vacancies are either mobile or immobile. By using combined electric DC and Electrical Impedance Spectroscopy (EIS) techniques we were able to develop and test a model which can explain different hysteretic I-V responses or pseudo-inductive loops found in impedance spectra as a consequence of the change of resistive states.
Also the influence of PLD parameters on the conductivity of SrTiO3 thin films as well as on their resistive switching behavior was studied in detail. By using microelectrodes, it was investigated how certain areas of a SrTiO3 thin film either required a forming process for reversible resistive switching or not. We propose critical defects distributed in the thin films to explain experiments with differently sized microelectrodes.
Additionally, the influence of the PLD process itself is critically discussed. For this purpose, we use a newly developed in-situ technique combining pulsed laser deposition and electrical DC or electrochemical impedance measurements. Recent results show that interactions with the plasma plume and/or the UV light has a strong impact on the electrical properties of oxide thin films. Interestingly, PLD interactions were even found to affect strontium titanate substrates used for deposition.