SCANNING FORCE MICROSCOPY OF FERROELECTRIC CRYSTALS

We report on the recent investigations of the surface of ferroelectric crystals with scanning force microscopy. Our inspection of the ferroelectric crystals triglycine-sulphate (TGS) and Barium-titanate (BaTiO3) allowed the simultaneous investigation of topographic surface features and ferroelectric domain structure in these crystals. Ferroelectric domains are clearly discernible in the non-contact mode as well as the friction force mode of imaging. In-situ investigations are demonstrated for temperatures T above the transition temperature T-c for TGS and BaTiO3 (T-c,T-TGS = 49 degrees C, T-c,T-BaTiO3 = 126 degrees C). We directly observed transition from the ferroelectric into the paraelectric phase. Upon cooling, new domains were formed indicating no memory effect, i.e. new domains grew on other spots than before heating. Further, a significantly different type of surface decoration was found for positively and negatively charged surface domains in TGS. This allows the in-situ observation of both domain wall motion and the nucleation of new domains.