Epitaxial Bi4Ti3O12 (BTO) films with La0.5Sr0.5CoO3 (LSCO) or Pt bottom electrodes were grown on MgO(001) substrates by pulsed laser deposition. Surprisingly, a symmetric Pt/BTO/Pt capacitor showed a highly asymmetric polarization switching and an asymmetric Pt/BTO/LSCO capacitor revealed a nearly symmetric polarization switching. To understand these intriguing phenomena, Auger electron spectroscopy and x-ray photoemission spectroscopy depth-profiles were used. The evidences for interdiffusions at the bottom BTO/Pt interface were found. To get further understanding on the interfacial states, a capacitance-voltage (C-V) measurement was performed on the Pt/BTO/Pt capacitor. By fitting the C-V data with a back-to-back Schottky diode model, built-in voltages at the top and the bottom interfaces were determined to be 1.1 V and 3.2 V, respectively. From the obtained built-in voltages, an asymmetric band diagram for the Pt/BTO/Pt structure was suggested. Therefore, the imprint failure can be explained by existence of asymmetric interfacial states.
|Number of pages||6|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - 1997|
|Event||Proceedings of the 1997 MRS Spring Meeting - San Francisco, CA, USA|
Duration: 31 Mar 1997 → …