Observation of domain walls in pzt thin film using sndm

4 Observation of domain walls in PZT thin film using SNDM 

Several studies have examined the thickness of the domain wall in ferroelectric materials [17]. The 90° a-c domain wall thickness has been measured using a transmission electron microscope (tem), [14] but distinguishing the positive and negative domains in 180° opposite polarization areas is difficult because these methods are used to observe the strain of arrangements of molecules. Direct clarification of the domain wall thickness is important with respect to both scientific and engineering aspects. 

Therefore we observed the 90° a-c domain walls and the 180° c-c domain walls in the above mentioned same epitaxial pzt thin film grown on SrTiOo using sndm. 

In the case of the a-c domain wall, the boundary of a-domain and c-domain is constructed to include lattice strain in order to match the length of the a-axis and the c-axis. On the other hand, in the case of the c-c domain wall, the lattice lengths do not need to match. Therefore, the c-c domain wall does not contain strain, which depends on lattice mismatching. As a result, the c-c domain wall appears to be smaller than the a-c domain wall. Based on the above result, we determined experimentally that the 180° c-c domain wall is thinner than the 90° a-c domain wall. 

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