Tailoring the Properties of Artificially Layered Ferroelectric Superlattices

Abstract

The polarization of PbTiO3/SrTiO3 superlattices is experimentally tuned from 0-60 mu C/cm(-2) and the transition temperature from room temperature to 1000 K while maintaining a perfect crystal structure and low leakage currents (see figure). A simple model based on Landau theory is developed as a guide for the straightforward production of samples with ferroelectric properties designed for particular applications

Extrinsic and Intrinsic Charge Trapping at the Graphene/Ferroelectric Interface

“…The temperature of 250°C was chosen in light of the previous results on successful removal of physisorbates from ferroelectric systems within the temperature range of 200°C -350°C 14,15 , which enhanced the subsequent piezoresponse of these materials. This temperature is also instrumental in reducing the polarization of PTO/STO superlattices based on a previous work in characterizing these heterostructures at different temperatures 11 . For the superlattices in this work, an estimated 75% reduction in polarization is expected at 250°C; this further contributes to the reduction of surface adsorbates.…”

Piezoelectric enhancement of(PbTiO3)m/(BaTiO3)nferroelectric superlattices through domai

“…Indeed, enhanced permittivity [10] and recovery of ferroelectricity [11], originating from the complex phase interactions at the layer interfaces, have been discovered in superlattices [12,13]. Recently, polarization rotations were engineered by modulating the biaxial strain [14] and layer volume fraction [15] in PbTiO 3 /SrTiO 3 and PbTiO 3 /CaTiO 3 superlattices, respectively.…”

Modeling of hysteresis loop and its applications in ferroelectric materials

“…Thus, equation (6) has been used to fit the observed hysteresis loops from experimental in BFO(Bi0.875Sm0.125FeO3) [25], NBT(Na0.5Bi0.5TiO3) [26], BTO(BaTiO3) [27] and PZT [28]. If we define the negative coercive field location as the left side of a hysteresis loop, and the positive coercive field location as the right side of a hysteresis loop, the hysteresis loop can be divided into left and right branches.…”

“…The intrinsic parameters in the left loop are consistent with the right ones. In equation (6), k, U, h and d are the related parameters during experimental measurement. In previous discussions, we correspond the saturation of polarization, the coercive field, and the slope of the hysteresis loop on the symmetric center to the parameters of k , d and h respectively.…”

“…Experimentally, the hysteresis loops can be measured while a periodical electric field or stress being applied onto the ferroelectrics externally [6][7]. Furthermore, many factors, such as temperature, grain boundaries or phase boundaries, doping, and anisotropy etc., which can affect the hysteretic behaviors of the ferroelectrics, have also been studied extensively [8][9][10][11][12].…”