Emergence of low dimensional ferroelectricity in Pr0.67Ca0.33MnO3 nanocrystal arrays

We discuss the emergence of low dimensional ferroelectricity in self-organized Pr0.67Ca0.33MnO3 nanocrystalline arrays deposited on a Si substrate. We observe sharp switching of the electric polarization under an external electric field with nearly rectangular hysteresis loops which persist up to 150 K. We discuss the polarization switching kinetics within the framework of the Kolmogorov-Avrami-Ishibashi model which gives a maximum domain wall speed of similar to 1 m s(-1). Polarized Raman spectroscopy shows evidence of isolated ferroelectric domains even at room temperature.