Multidomain switching in the ferroelectric nanodots

Abstract

Controlling the polarization switching in the ferroelectric nanocrystals, nanowires and nanodots has an inherent specificity related to the emergence of depolarization field that is associated with the spontaneous polarization. This field splits the finite-size ferroelectric sample into polarization domains. Here, based on 3D numerical simulations, we study the formation of 180 • polarization domains in a nanoplatelet, made of uniaxial ferroelectric material, and show that in addition to the polarized monodomain state, the multidomain structures, notably of stripe and cylindrical shapes, can arise and compete during the switching process. The multibit switching protocol between these configurations may be realized by temperature and field variations.

Numerical modeling and investigations of 3D devices with ferroelectric layer fully embedded in a paraelectric environment

“…In addition to these, the Obvious Profile, denoted by (OP) and corresponding to the case where P h ≡ 0, occurs from simulations performed here. Some of the obtained profiles have already been observed in other works (see, e.g., [16,25]); for instance, a profile analogous to (3BP) as well as to (4BP), namely the 2-bands profile, has been found experimentally in the case of a nanofilm of Lead Titanate (see [25]). Now, we specify how to achieve numerically the heating or cooling of the device.…”

“…Let us mention furthermore that the volume of any considered ferroelectric layer Ω f , in order to avoid to disturb the emergent fringing field (see, e.g., [16]), will be of course sufficiently more small than the one of the medium Ω, but not too small. In particular also, the related considerations will not then be subject to numerical instabilities in experiments, although the asymptotic framework developed by H. Ammari et al in [1] may remedy this issue.…”

“…In this work, we are concerned with 3D devices made up of a ferroelectric layer that is fully embedded in a paraelectric environment, and where the geometrical configurations of nanofilms, nanorods or nanodots can be considered. We are namely interested in an extended frame of investigations in the sense that the considerations of the physical and geometrical parameters can be also the ones that are not systematically in correspondence with particular concrete situations, in contrast with [16] where the considerations of the parameters are essentially related to applications by involving furthermore the geometrical context of nanodots.…”

Ferroelectric multiple-valued logic units

“…The first level is connected to the memory of PLA to read the coefficients. x2 x1 a (0) a (1) a (2) a (3) a (4) a (5) a (6) a (7) a (8) a (9) a (10) a (11) a (12) a (13) a (14) a (15) a (16) a (17) a (18) a (19) a (20) a (21) a (22) a (23) a (24) a (25) a (26) M L Figure 4. The detailed structure of the PLA for implementation of 3-valued function on 3 variables…”

Ferroelectric symmetry-protected multibit memory cell

“…Here we show that these states enable the design of the enhanced performance memory units, ferrolectric multibit cells (FMBC), with the non-trivial topological access to the memory levels by the specific protocol of the applied electric field. The advantage offered by the FMBC as compared to other widely discussed implementations of MLC based on the either of the spin-torque memristive effect 9 , the domain formation in ferroelectric nanodots 10 , the hybrid design 11 12 , the DNA-based storage 13 , and the sequential polarization rotation 14 , to name a few, is that while maintaining the simplicity of the material realization, the FMBC ensure the symmetry protection of the memory levels and the strain-temperature programmable architecture of accessing stored information.…”