Nanocrystalline alkaline earth titanates and their electrical conductivity characteristics under changing oxygen ambients

Electroceramic materials, especially the perovskite-type titanates, have been subject of intense research in recent years aiming for their integration into state-of-the-art electronic devices like memories or sensors. Due to continuous miniaturization, typical feature dimensions range down to several nanometers. Today, the discussion of thin film electrical behavior (like leakage currents or degradation effects) is still based on the established model of bulk defect chemistry. However, the observed electrical properties of thin films are often inconsistent with this model. Against the background of single crystals, the present work represents the first systematic study of the conductivity characteristics of alkaline Earth titanates in the form of polycrystalline and heteroepitaxial thin films as well as nanocrystalline ceramics as a function of temperature and the ambient oxygen partial pressure. This was made possible by using a specially designed measurement setup that allowed the reliable determination of resistances of up to several gigaohms at temperatures between 600 C and 1000 C under continuously adjustable oxygen partial pressures ranging from 10"-"2"0 bar to 1 bar. (orig.)Available from TIB Hannover: RA 831(4070) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman