Electric field induced structural modifications in metal/SrTiO3 junctions and their resistive properties

In oxides with perovskite-type of structure, mobile oxygen can cause the formation of non-stoichiometric regions when an electric field of sufficient strength (∝1000 V/mm) is applied. Our in-situ investigations of metal/SrTiO3 junctions revealed reversible structural changes at room temperature caused by a systematic field-induced redistribution of oxygen. The investigations were carried out using wide-angle X-ray scattering, X-ray absorption spectroscopy, photoluminescence, nanoindentation and time-dependent electric I-U measurements. Motivated by the successful use of SrTiO3 with different doping metals for memory cells on the basis of resistive switching combined with the findings on the major importance of oxygen vacancy redistribution, we show the possibility of realizing a resistance change memory based on vacancy-doped SrTiO3. The formation of corresponding metal/SrTiO3 junctions in an electric field is discussed as well as the switching between ohmic and Schottky-type resistive properties. A notable hysteresis in the I-U characteristics can be used to carry out Write, Read and Erase operations to test the memory cell properties of such junctions.