Scanning probe microscopy observation of nanoscale domain switching in sol–gel PbTiO3 thin films

In this paper, we present direct observations of local domain switching in the individual grains of 300 nm thick sol–gel PbTiO3 thin films using a piezo-response SPM. It is revealed that almost no domain switching occurs in the c-domain region at 4 V, and partially switching takes place at 6 V. The switched domain expends the whole grain rapidly by further increasing the bias. The a-domain cannot be reoriented even at the bias up to 10 V. High tetragonality of PbTiO3 is believed to induce great strain to suppress the reorientation of a-domains. The polarization contrast difference at various bias voltages may originate from the non-switchable polarization near the bottom electrode and the partially switched domain.