NANOSCALE FERROELECTRICS MACHINED FROM SINGLE CRYSTALS

ABSTRACT

This paper summarises some of the most recent work that has been done on nanoscale ferroelectrics as a result of a joint collaborative research effort involving groups in Queen's University Belfast, the University of Cambridge and the University of St. Andrews. Attempts have been made to observe fundamental effects of reduced size, and increasing morphological complexity, on ferroelectric behaviour by studying the functional response and domain characteristics in nanoscale single crystal material, whose size and morphology have been defined by Focused Ion Beam (FIB) patterning. This approach to nanoshape fabrication has allowed the following broad statements to be made:

(i) in single crystal BaTiO₃ sheets, permittivity and phase transition behaviour is not altered from that of bulk material down to a thickness of ∼ 75 nm;

(ii) in single crystal BaTiO₃ sheets and nanowires changes in observed domain morphologies are consistent with large scale continuum modeling.