| Scanning force microscopy (SFM) has been becoming the key tool and approach to the investingations of ferroelectric thin film's domain structures and characteristics. SFM consists of many kinds of modes which have been used in the various material researches. Among these modes, piezoresponse force microscopy is the dominating method to the study of ferroelectric thin films. It can map domain structures of ferroelectric thin films with high revolution. In this work, we discussed the factors which cause the factitious signals in domain maps. These artifacts can be induced by the state of SFM tip and the formation of the sample surface, which results in the misreading of the domain maps. Ferroelectric fatigue is much fatal for the electric apparatus based on the switchable polarization, such as non-volatile random access memories (NVFRAM). PFM was utilized to investigate fatigue effect in ferroelectric thin films. We observed the evolution of PbZrxTi1-xO3(PZT) thin film domain structures in the process of fatigue with PFM. It may be concluded that the fatigue is mainly resulted from the domain wall pinning. PFM also was used to switch the domain structures. After mapping domain switching process in real time, the retention of polarization was discovered in the La3+ doped SrBi2Ta2O9(SBLT)thin film. We studied the special structure of SBLT dedicatedly, and dug the root of the phenomenon -90o domain switching occurred in the SBLT thin film. Moreover, the many varieties of pinning domain structures were visualized with PFM through the polarizing by applied DC bias. Besides these effects and characteristics according to the ferroelectric domain, piezoelectric constant and surface energy correlated to internal stress of thin film can be measured with SFM. Though the SFM measurement of piezoelectric constant is not accurate enough, it supports... |
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