PROBLEMS ASSOCIATED WITH IMAGING RESISTIVE BARRIERS IN BATIO3 PTC CERAMICS USING THE SEM CONDUCTIVE MODE

The micro-electrical properties of BaTiO3 have been studied using the remote electron beam induced current technique. Difficulties associated with applying this technique to low resistance, inhomogeneous ceramics are discussed and illustr ated with the example of PTCR materials. At temperatures above the Curie temperature, contrast steps corresponding to resistive interfaces are observed with differing sensitivities according to the imaging conditions used. The image noise decreases and the current sensitivity increases with the sample resistance. Remote electron beam induced current contrast in BaTiO3, showing the high resistivity transition does not occur uniformly as a function of temperature across all grain boundaries.