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Interfaces and domains in ferroelectrics and multiferroics

PhD researcher: Sriram Venkatesan

The piezoelectric and dielectric properties of ferroelectric perovskites can be greatly enhanced by reducing the symmetry elements, in particular by eliminating the "easy axis" along which the polarization vector is usually constraint. The objective of this project is to create such systems artificially by controlling the growth at the nanoscale. In particular, we study the critical thickness for ferroelectricity and local variation in surface charge ordering at an atomic scale in transition-metal (perovskite) oxides with electron-holography techniques and scanning probe microscopy. The use of High Resolution TEM together with electron holography to provide information about both the atomic order, the structural domains and defects (dislocations) and the local electric polarization in ferroelectric (multi-ferroic) thin films, which together define the ferroelectric and ferromagnetic response of these films. (Together with dr. B.J. Kooiand in collaboration with prof. Beatriz Noheda).

ferroelectrics

Figure: XTEM Analysis of PbTiO3 Thin Films on DyScO3