'Evolution of electric field amplitude dependent scaling behaviors in ferroelectric films over a broad temperature range'
　　  As a primary non-equilibrium phenomenon in ferroelectric films, the dynamic hysteresis character has become an important focus since the dynamic response of hysteresis can evaluate the key kinetic picture of nucleation, growth and motions of domains, thus also provide a lot of information critical for many ferroelectric applications, especially for ferroelectric random access memories (FeRAMs). At low frequency end, the dynamic hysteresis behavior can be disclosed by a so-called scaling power law, i.e., A∝E₀^αf^β, where α=2/3 and β=1/3. However, it is far beyond clear in the correlations between the the dynamic hysteresis behavior and the polarization microstructure. Besides, there are some leakage current induced ferroelectric-like hysteresis loops, usually misleading nonferroelectric or artifacts to be the true ferroelectric one. A quantitative criterion between the ferroelectric hysteresis and the artificial one is still absent.

In present letter, the temperature dependent ferroelectric and dielectric characteristics of 0.5mol% Mn doped Pb_0.5Sr_0.5TiO₃ (PSMT05) and 0.7Pb(Mg_1/3Nb_2/3)O₃-0.3PbTiO₃ (0.7PMN-0.3PT) films were reported and a careful analysis on the evolution of the electric field amplitude dependent scaling behaviors over a broad temperature range was also addressed. It is found that It is found that (1) at T

This research results not only elucidate the mechanisms behind correlation between scaling behaviors and evolution of polarization microstructures, e.g. domains, polar micro-regions, and also provide a quantitative criterion between the ferroelectric hysteresis and the artificial one. This work has been published in Applied Physics Letters.[ Appl. Phys. Lett. 93, 092908 (2008)]

Figure 1. The hysteresis loops of PSMT05 film measured with the measure frequency of 1 kHz and various amplitude voltages at (a) 100K, (b) 300K, (c) 420K and (d) 560K. (e) is the temperature dependence of Pr and Vc at the maximal voltage of 24V.

Figure 2. Scaling plots of the hysteresis loop area dependence on electric field amplitude at several typical temperature regions using power law A∝V₀^α with (a) α=2/3, (b) α=1, (c) α=2 in PSMT05 film.

Figure 3. The temperature dependence of the scaling exponent α for PSMT05 film and (the inset) 0.7PMN-0.3PT film.