Flexoelectric Control of Defect Formation in Ferroelectric Epitaxial Thin Films

Lee, Daesu; Jeon, Byung-Chul; Yoon, Aram; Shin, Yoo Jin; Lee, Myang Hwan; Song, Tae Kwon; Bu, Sang Don; Kim, Miyoung; Chung, J.-S.; Yoon, Jong‐Gul; Noh, Tae Won

doi:10.1002/adma.201400654

Cited by 91 publications

(66 citation statements)

References 39 publications

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“…When the BFO film is grown, a structural change ( e.g . strain relaxation) occurs along the step-terrace edge, generating a locally-induced internal field43, which can be described by the pinning potential energy landscape . Domain wall pinning sites, located at local minima of , hinder domain wall motion.…”

Section: Resultsmentioning

confidence: 99%

“…The BFO thickness, measured by scanning electron microscopy (SEM) on the sample edge, was 280 nm on LSMO and 232 nm on SRO. Further details on the structural and physical properties are published in previous reports4344. Capacitor structures – μm 2 in size were fabricated by depositing 40 nm thick Pt by dc magnetron sputtering and patterning using conventional photolithography.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Suppression of creep-regime dynamics in epitaxial ferroelectric BiFeO3 films

Jeon

Yang

Hwang

et al. 2015

Sci Rep

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Switching dynamics of ferroelectric materials are governed by the response of domain walls to applied electric field. In epitaxial ferroelectric films, thermally-activated ‘creep’ motion plays a significant role in domain wall dynamics, and accordingly, detailed understanding of the system’s switching properties requires that this creep motion be taken into account. Despite this importance, few studies have investigated creep motion in ferroelectric films under ac-driven force. Here, we explore ac hysteretic dynamics in epitaxial BiFeO3 thin films, through ferroelectric hysteresis measurements, and stroboscopic piezoresponse force microscopy. We reveal that identically-fabricated BiFeO3 films on SrRuO3 or La0.67Sr0.33MnO3 bottom electrodes exhibit markedly different switching behaviour, with BiFeO3/SrRuO3 presenting essentially creep-free dynamics. This unprecedented result arises from the distinctive spatial inhomogeneities of the internal fields, these being influenced by the bottom electrode’s surface morphology. Our findings further highlight the importance of controlling interface and defect characteristics, to engineer ferroelectric devices with optimised performance.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Suppression of creep-regime dynamics in epitaxial ferroelectric BiFeO3 films

Jeon

Yang

Hwang

et al. 2015

Sci Rep

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“…Different lattice relaxation processes could generate strain gradients in the films, which could imply a flexoelectric field. The effects of these supplementary fields lead to different behaviours in polarization switching, shift of the hysteresis loop along Epitaxyvoltage axis, modification of remnant polarization and occurrence of diode-like current characteristics with dependence on polarization direction [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Electrical Properties of Epitaxial Ferroelectric Heterostructures

Boni¹,

Chirilă²,

Negrea³

et al. 2018

Epitaxy

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In the context of miniaturization of devices, ferroelectric materials are used as multifunctional materials for their well-known intrinsic properties, especially for the switching of polarization in an applied electric field. The high-quality epitaxial thin film structures are used for the possibility to study different effects as low dimensions, interface, strain and strain gradients on ferroelectric materials and other electric characteristics, also representing a possibility to obtain new phenomena and properties that can be used for development of new devices with different functionalities. This chapter is a summary of the ferroelectric and dielectric behaviour of epitaxial thin films of Pb(Zr,Ti)O 3 (PZT) and BaTiO 3 (BTO) obtained by pulsed laser deposition and the correlation with structural quality of the layers and with different electrostatic conditions induced either by electrodes or by the different interlayers. For this purpose in the first part, studies regarding the influence of the substrates and of different top electrodes are performed for Pb(Zr,Ti) O 3 (PZT) 52/48. In the second part, we focused on artificial multiferroic structures from alternating layers of PZT 20/80 or BaTiO 3 (BTO) as ferroelectric phase and CoFe 2 O 4 (CFO) as magnetic material. We found that interface configuration and strain engineering could control ferroelectric hysteresis, the capacitance or the leakage current magnitude.

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“…[1][2][3] The ferroelectric polarization switching mechanism is assisted by defects, including external inclusions and dislocations with low nucleation energies. [4][5][6][7][8][9] The charged defects can combine together to form defect dipoles in the BiFeO 3 , such as (V Fe 00 À V •• o ). 10,11 These defect dipoles are reported to affect both film conductivity and polarization.…”

Section: Thin Film I Introductionmentioning

confidence: 99%