Statics and Dynamics of “Charged” Interfaces in Electroceramics

Abstract A large number of electroceramics derive their technologically useful and scientifically appealing properties via electrically active (charged) interfaces.[l] These interfaces can be simple grain boundaries in, for example, varistors, to complicated domain configuration in ferroelectric thin films. Several common issues relate to virtually all electrically active interfaces. The electrical activity of such interfaces is usually a consequence of trapping of charged electronic and/or ionic defects. Such trapping leads to compensating charge of opposite sign across the interfaces, viz. space-charge region. Collectively, they influence and often dominate a wide variety of phenomena, ranging from formation of Schottky barriers to impedence to domain boundary motion. While bulk measurements, either electrical (e.g. P-E, C-V, I-V), optical (e.g. Raman) or resonance (e.g. EPR) have contributed significantly to the understanding of charged interfaces, there are very few direct observations of electrical activity of interfaces at a length-scale which is essential (i.e. 1- 10 nm).