Direct Observations of Retention Failure in Ferroelectric Memories

Gao, Peng; Nelson, Christopher T.; Jokisaari, Jacob R.; Zhang, Yi; Baek, Seung Hyub; Bark, Chung Wung; Wang, Enge; Liu, Yuanming; Li, Jiangyu; Eom, Chang‐Beom; Pan, Xiaoqing

doi:10.1002/adma.201103983

Cited by 59 publications

(58 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2b, a new À c-domain (where the negative sign indicates downward polarization) nucleates and grows at the top interface at a bias of 8.2 V, leading to the contrast change from bright to dark. Although previous studies proposed that the nucleation of c-domains preferentially begins from 90°domain walls 3,8,15 , our in situ TEM observations revealed that nucleation occurs only at the top interface with a negative bias 5,10 . The switched À c-domain grew with increasing voltage (Fig.…”

Section: Resultscontrasting

confidence: 90%

“…For the thin film geometry with an electrically conductive bottom electrode under an applied bias, fixed electrical potential boundary conditions at the film surfaces were used to solve equation (5). For the planar bottom electrode in the system, the potential was held uniformly constant at zero bias throughout the simulation.…”

Section: Methodsmentioning

confidence: 99%

“…For this simulation, its value was chosen to be G 1111 /G 110 ¼ 0.6 in reduced units. Using equations (3)(4)(5)(6)(7)(8)(9)(10), the temporal evolution of the thin film under an applied potential was obtained by using a linear approximation to the time derivative in equation (1) and solving the resulting equation using the semi-implicit Fourier spectral method 22 . This method applies periodic boundary conditions in the x 1 and x 2 dimensions while applying the specified boundary conditions in the out-of-plane x 3 dimension.…”

Section: Methodsmentioning

confidence: 99%

“…These ferroelastic domains also lead to a decrease in the relative stability of a written domain structure and have been seen to be associated with back switching of the thin film to its initial state after the removal of the applied electric field 3,4 . This behaviour is especially important in nonvolatile devices as their ability to retain the current state is determined by the stability of newly written domains 5 .…”

mentioning

confidence: 99%

See 3 more Smart Citations

Atomic-scale mechanisms of ferroelastic domain-wall-mediated ferroelectric switching

et al. 2013

Self Cite

View full text Add to dashboard Cite

Polarization switching in ferroelectric thin films occurs via nucleation and growth of 180°d omains through a highly inhomogeneous process in which the kinetics are largely controlled by defects, interfaces and pre-existing domain walls. Here we present the first real-time, atomic-scale observations and phase-field simulations of domain switching dominated by pre-existing, but immobile, ferroelastic domains in Pb(Zr 0.2 Ti 0.8 )O 3 thin films. Our observations reveal a novel hindering effect, which occurs via the formation of a transient layer with a thickness of several unit cells at an otherwise charged interface between a ferroelastic domain and a switched domain. This transient layer possesses a low-magnitude polarization, with a dipole glass structure, resembling the dead layer. The present study provides an atomic level explanation of the hindering of ferroelectric domain motion by ferroelastic domains. Hindering can be overcome either by applying a higher bias or by removing the as-grown ferroelastic domains in fabricated nanostructures.

show abstract

Section: Resultscontrasting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Atomic-scale mechanisms of ferroelastic domain-wall-mediated ferroelectric switching

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…This relationship between dynamic domain behaviour and microstructure remains unclear since it is difficult to extract these details from the large area aggregate responses measured with bulk techniques, such as X-ray diffraction or electrical characterization, or with surface probe techniques that provide limited subsurface microstructure information 2,[6][7][8][9][10]15 . Recently developed in situ transmission electron microscopy (TEM) techniques, which enable switching behaviour to be correlated with specific microstructure and defects, provide a unique opportunity for domain dynamics studies 12,[19][20][21][22][23] .…”

mentioning

confidence: 99%

Ferroelastic domain switching dynamics under electrical and mechanical excitations

et al. 2014

Self Cite

View full text Add to dashboard Cite

In thin film ferroelectric devices, switching of ferroelastic domains can significantly enhance electromechanical response. Previous studies have shown disagreement regarding the mobility or immobility of ferroelastic domain walls, indicating that switching behaviour strongly depends on specific microstructures in ferroelectric systems. Here we study the switching dynamics of individual ferroelastic domains in thin Pb(Zr 0.2 ,Ti 0.8 )O 3 films under electrical and mechanical excitations by using in situ transmission electron microscopy and phase-field modelling. We find that ferroelastic domains can be effectively and permanently stabilized by dislocations at the substrate interface while similar domains at free surfaces without pinning dislocations can be removed by either electric or stress fields. For both electrical and mechanical switching, ferroelastic switching is found to occur most readily at the highly active needle points in ferroelastic domains. Our results provide new insights into the understanding of polarization switching dynamics as well as the engineering of ferroelectric devices.

show abstract

Ferroelectric Domain Wall Memristor

McConville

Wang

et al. 2020

Adv Funct Materials

112

View full text Add to dashboard Cite

A domain wall‐enabled memristor is created, in thin film lithium niobate capacitors, which shows up to twelve orders of magnitude variation in resistance. Such dramatic changes are caused by the injection of strongly inclined conducting ferroelectric domain walls, which provide conduits for current flow between electrodes. Varying the magnitude of the applied electric‐field pulse, used to induce switching, alters the extent to which polarization reversal occurs; this systematically changes the density of the injected conducting domain walls in the ferroelectric layer and hence the resistivity of the capacitor structure as a whole. Hundreds of distinct conductance states can be produced, with current maxima achieved around the coercive voltage, where domain wall density is greatest, and minima associated with the almost fully switched ferroelectric (few domain walls). Significantly, this “domain wall memristor” demonstrates a plasticity effect: when a succession of voltage pulses of constant magnitude is applied, the resistance changes. Resistance plasticity opens the way for the domain wall memristor to be considered for artificial synapse applications in neuromorphic circuits.

show abstract

Direct Observations of Retention Failure in Ferroelectric Memories

Cited by 59 publications

References 32 publications

Atomic-scale mechanisms of ferroelastic domain-wall-mediated ferroelectric switching

Atomic-scale mechanisms of ferroelastic domain-wall-mediated ferroelectric switching

Ferroelastic domain switching dynamics under electrical and mechanical excitations

Ferroelectric Domain Wall Memristor

Contact Info

Product

Resources

About