Two-Step Polarization Switching in Ferroelectric Polymers

Wu, Yangjiang; Li, Xiaohui; Jonas, Alain M.; Hu, Zhijun

doi:10.1103/physrevlett.115.267601

Cited by 24 publications

(20 citation statements)

References 35 publications

(46 reference statements)

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“…Mechanical stress is another path to fabricate oriented P(VDF‐TrFE) for flexible FeRAM. Park and co‐workers demonstrated P(VDF‐TrFE) memory from effective alignment by shear stress, as applied stress reorients and reorganizes polymer chains . Hu et al have proposed nanoimprint lithography (NIL), which offers stress‐assisted alignment and patterns of polymers .…”

mentioning

confidence: 99%

“…Within a single lamella, the P(VDF‐TrFE) chains are aligned along out‐of‐plane direction of the lamella, folding back and forth . Irregular components including loose loops, tie segments, and dangling ends are mostly located between neighboring lamellae, namely the grain boundaries. Therefore, from the lamellar structure in SA films, we can conclude that the chain direction of polymer is aligned parallel to the film surface by the self‐assembly.…”

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confidence: 99%

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Flexible Robust and High‐Density FeRAM from Array of Organic Ferroelectric Nano‐Lamellae by Self‐Assembly

et al. 2019

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Ferroelectric memories are endowed with high data storage density by nanostructure designing, while the robustness is also impaired. For organic ferroelectrics favored by flexible memories, low Curie transition temperature limits their thermal stability. Herein, a ferroelectric random access memory (FeRAM) is demonstrated based on an array of P(VDF‐TrFE) lamellae by self‐assembly. Written data shows enhanced thermal endurance up to 90 °C and undergoes 12 thermal cycles between 30 and 80 °C with little volatilization. The promoted thermal stability is attributed to pinning effect at interfaces between grain boundaries and lamellae, where charged domain walls and charged defects are coupled. These results provide a strategy for improving robustness of organic flexible FeRAMs, and reveal an attracting coupling effect between different phases of ferroelectric polymer.

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confidence: 99%

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confidence: 99%

Flexible Robust and High‐Density FeRAM from Array of Organic Ferroelectric Nano‐Lamellae by Self‐Assembly

et al. 2019

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“…[7][8][9] There is energetic and spatial disorder due to, for instance, misfit dislocations, 10,11 defects in conformation and molecular packing of macromolecular chains, 12 and grain boundaries. 13,14 The presence of these defects lowers the barrier for polarization reversal. The collective rotation of dipoles is replaced by nucleation and anisotropic growth of individual domains, termed as extrinsic switching.…”

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confidence: 99%

Retention of intermediate polarization states in ferroelectric materials enabling memories for multi-bit data storage

Zhao

Katsouras

Asadi

et al. 2016

Applied Physics Letters

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A homogeneous ferroelectric single crystal exhibits only two remanent polarization states that are stable over time, whereas intermediate, or unsaturated, polarization states are thermodynamically instable. Commonly used ferroelectric materials however, are inhomogeneous polycrystalline thin films or ceramics. To investigate the stability of intermediate polarization states, formed upon incomplete, or partial, switching, we have systematically studied their retention in capacitors comprising two classic ferroelectric materials, viz. random copolymer of vinylidene fluoride with trifluoroethylene, P(VDF-TrFE), and Pb(Zr,Ti)O3. Each experiment started from a discharged and electrically depolarized ferroelectric capacitor. Voltage pulses were applied to set the given polarization states. The retention was measured as a function of time at various temperatures. The intermediate polarization states are stable over time, up to the Curie temperature. We argue that the remarkable stability originates from the coexistence of effectively independent domains, with different values of polarization and coercive field. A domain growth model is derived quantitatively describing deterministic switching between the intermediate polarization states. We show that by using well-defined voltage pulses, the polarization can be set to any arbitrary value, allowing arithmetic programming. The feasibility of arithmetic programming along with the inherent stability of intermediate polarization states makes ferroelectric materials ideal candidates for multibit data storage.

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“…In this section, we introduce an approach to reorient the direction of the in-plane polarization using a force microscopy tip. PFM is a tool regularly utilized for investigations of nanoscale ferroelectric switching in P(VDF-TrFE) films [19,[25][26][27][28]. At first, the film has been electrically poled by applying a tip voltage of 10 V in an area of several μm 2 .…”

Section: Resultsmentioning

confidence: 99%

Aligning in-plane polarization multiplies piezoresponse in P(VDF-TrFE) films on graphite

et al. 2018

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Ferroelectric polymers are promising as piezoelectric sensors and devices for data storage, energy harvesting and fast energy storage. However, efficient electric polarization as well as piezoelectric and dielectric responses of as-deposited films are often much lower than expected in a crystalline model, because the local orientations of electric dipoles show substantial disorder. Here we introduce an approach for in-plane alignment of the polarization based on applying soft mechanical pressure with a force microscopy tip. Micron-sized ferroelectric domains with well-defined in-plane and out-of-plane polarization orientation and low surface roughness have been written in poly(vinylidene fluoridetrifluoroethylene) (PVDF-TrFE) films on graphite. Inside such domains, the piezoelectric response is more than four times that of the untreated film. The achieved polarization alignment can advance the performance of many devices, since it reduces the cancellation of local responses to electric fields or mechanical strains resulting from polarization disorder.

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Two-Step Polarization Switching in Ferroelectric Polymers

Cited by 24 publications

References 35 publications

Flexible Robust and High‐Density FeRAM from Array of Organic Ferroelectric Nano‐Lamellae by Self‐Assembly

Flexible Robust and High‐Density FeRAM from Array of Organic Ferroelectric Nano‐Lamellae by Self‐Assembly

Retention of intermediate polarization states in ferroelectric materials enabling memories for multi-bit data storage

Aligning in-plane polarization multiplies piezoresponse in P(VDF-TrFE) films on graphite

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