| AVS 59th Annual International Symposium and Exhibition | |
| Applied Surface Science | Thursday Sessions |
| Session AS-ThA |
| Session: | Applications of Large Cluster Ion Beams - Part 2 (2:00-3:20 pm)/ Surface Analysis using Synchrotron Techniques (3:40-5:40 pm) |
| Presenter: | F. Offi, CNISM and Dipartimento di Fisica, Università Roma Tre, Italy |
| Authors: | F. Offi, CNISM and Dipartimento di Fisica, Università Roma Tre, Italy F. Borgatti, CNR-ISMN, Bologna, Italy Y. Yamashita, Synchrotron X-ray Station at SPring-8, NIMS, Japan A. Yang, Synchrotron X-ray Station at SPring-8, NIMS, Japan M. Kobata, Synchrotron X-ray Station at SPring-8, NIMS, Japan K. Kobayashi, Synchrotron X-ray Station at SPring-8, NIMS, Japan C. Park, Peter Grünberg Institut, Research Center Jülich, Germany A. Herpers, Peter Grünberg Institut, Research Center Jülich, Germany R. Dittmann, Peter Grünberg Institut, Research Center Jülich, Germany G. Panaccione, CNR-IOM, Basovizza-Trieste, Italy |
| Correspondent: | Click to Email |
Electrical pulse induced resistance change has been observed at several oxides interfaces but its microscopic origin is still an open issue. In order to shed light on this problem we investigated with hard x-ray photoemission spectroscopy (HAXPES) the interface electronic structure of Ti covered 40 nm PrCaMnO3 (PCMO) film within SrRuO3/PrCaMn03/Ti/Pt devices exhibiting resistive switching behaviour. In particular, we searched for differences arising among the spectra of the virgin (not formed) and the high-resistivity states (HRS). The electronic structure of the Ti top electrode has been probed by measuring the Ti 2p spectra. The identification of the Ti 2p chemical states on the basis of literature binding energy (BE) values, indicate that the dominant Ti peak at lower BE corresponds to metallic state. Evidence is also found for the presence of Ti(IV) chemical state, due to the formation of TiO2, and of other intermediate oxide species. Interestingly, the peak corresponding to Ti(IV) is more intense for the HRS than for the virgin state of the samples, suggesting that formation of Ti oxide is induced in the HRS thorough redox reactions related to the migration of oxygen ions from the PCMO inside the Ti layer. Moreover, the core-level spectra of all the elements of the PCMO layer, when compared to the spectra of the reference (uncovered) thick films of these materials, show BE shift and a change of the spectral lineshape that strongly resembles the BE shift dependence of the photoemission spectra on the amount of hole doping, which is related to the change of the chemical potential. Therefore the HAXPES results show changes of the PCMO and Ti electronic structure for this manganite heterostructure, indicating the increment of Ti oxide in the high-resistivity state and pinning of the PCMO chemical potential.