Impact of the tip radius on the lateral resolution in piezoresponse force microscopy

We present a quantitative investigation of the impact of tip radius as well as sample type and thickness on the lateral resolution in piezoresponse force microscopy (PFM) investigating bulk single crystals. The observed linear dependence of the width of the domain wall on the tip radius as well as the independence of the lateral resolution on the specific crystal-type are validated by a simple theoretical model. Using a Ti-Pt-coated tip with a nominal radius of 15 nm the so far highest lateral resolution in bulk crystals of only 17 nm was obtained

Transient enhancement of photorefractive gratings in lead germanate by homogeneous pyroelectric fields

During holographic recording in pure (Pb5Ge3O11) and doped [(Pb1−xBax)5Ge3O11] lead germanate crystals, the diffraction efficiency is transiently enhanced at the initial stage. The enhancement is studied as a function of writing-beam intensity and of dark delay time between two successive recording processes and with open- or short-circuited crystal surfaces. Homogeneous pyroelectric fields that arise from heating of the crystals by cw illumination are revealed to be the main mechanism for diffraction efficiency enhancement. The combined effect of pyroelectric fields and charge compensation is analyzed and used for the explanation of the observed phenomena