Electron microscopy enters the picometer scale

Using electron microscope methods of a hitherto unknown accuracy, scientists from Forschungszentrum Juelich have succeeded in locally demonstrating polarization in the ferroelectric PbZr0.2Ti0.8O3 and measuring it atom by atom. The broken line forms the boundary of two areas with different electrical polarization marked by the arrows. This is due to the fact that the atoms (Pb: lead; Z: zircon; Ti: titanium; O: oxygen) are displaced from their positions and therefore their electrical charges cannot compensate for each other. On the left, the oxygen atoms are displaced 38 pm downwards, and on the right to the same degree upwards out of the zircon/titanium atomic row. This row itself is displaced vertically by 10 pm from the center line between the lead atoms. In order to write information in applications for data storage, the boundary between these two areas of different polarization directions is displaced to the left or to the right so that only one polarization direction exists in the material. Image: Forschungszentrum Juelich