Electric modulation of conduction in multiferroic Ca-doped BiFeO3 films

Yang, Chan−Ho; Seidel, Jan; Kim, S. Y.; Rossen, Pim B.; Yu, Pu; Gajek, M.; Chu, Ying Hao; Martin, Lane W.; Holcomb, Mikel B.; He, Qing; Maksymovych, Peter; Balke, Nina; Kalinin, Sergei V.; Baddorf, Arthur P.; Basu, Soumen; Scullin, Matthew L.; Ramesh, R.

doi:10.1038/nmat2432

Cited by 497 publications

(376 citation statements)

References 40 publications

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“…22 According to the Nernst-Einstein relation, we note that the diffusivity of V O 2 þ can vary by many orders of magnitude for the typical activation energy of B1.0 eV of various perovskite oxides. 23,24 In Figures 5a and c, we show that the single-domain switching and the related photovoltaic characteristics remained qualitatively unchanged, regardless of the E-field poling temperatures. We only observed a small increase in I ph at 300 K. In the multidomain channel, however, domain reversal became notably inhomogeneous at 77 K, as shown in Figure 5b, leading to the absence of photovoltaic characteristics, as shown in Figure 5d.…”

Section: Resultsmentioning

confidence: 87%

Single ferroelectric-domain photovoltaic switch based on lateral BiFeO3 cells

Sung

Lee

et al. 2013

NPG Asia Mater

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The bistability of ferroelectric polarization states serves as a basis for solid-state memory. This phenomenon can also yield an interesting photovoltaic effect in such a way that the directional photocarrier motion follows the inherent potential gradient imposed by the ferroelectric polarization vectors. Here, we demonstrate a single-domain photovoltaic switch based on lateral BiFeO 3 channels, in which such photovoltaic switching is achieved by a coherent single-domain reversal with a short electrical pulse. We then provide visual evidence for such operations with a series of spatially and spectrally resolved short-circuit photocurrent images. Specifically, we reveal that the sequential photovoltaic current images directly reflect the remanent polarization states of a single-domain channel. We also verify that, in multidomain channels, diffusive switching characteristics are determined not only by the internal polarization vector within the domain but also by oxygen vacancy accumulation at the domain walls. Keywords: ferroelectrics; multiferroics; oxide photonics; photovoltaics INTRODUCTIONHomogeneous light illumination on non-centrosymmetric crystals, such as ferroelectrics, in the intrinsic absorption range can give rise to an interesting photovoltaic effect, dubbed as the bulk photovoltaic effect. 1,2 This effect is distinct from that of typical semiconductor p-n junction photovoltaics and excitonic heterojunction photovoltaics in that the photogenerated carriers can be separated along the inherent polar directions, ensuing the unidirectional photocurrent (I ph ) and photovoltage (V ph ), associated with the spontaneous ferroelectric polarization vector (P s ). Therein, the open-circuit voltage (V oc ) is determined by the magnitude of the remanent polarization of ferroelectrics, and it can be additively as large as a few hundreds of volts, although the short-circuit current (I sc I ph at 0 V) is low due to the insulating character of the system. This phenomenon has been recently revisited with a small band-gap, BiFeO 3 (BFO) ferroelectric, from which a substantially higher photon-to-charge generation efficiency can be achieved in the visible range compared with that of other insulating ferroelectrics. [3][4][5][6][7][8] reported that diodelike rectification follows the polarization-dependent interface bandbending of BFO single-crystal slabs that are electrically switchable, that is, V oc and I sc are defined by the remanent polarization directions. In general, the spatial extent of spontaneous polarization vectors in ferroelectric crystals is typically manifested as domains (typically spanning over a few mm in size) and domain walls (DW, 1-2 nm in

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Section: Resultsmentioning

confidence: 87%

Single ferroelectric-domain photovoltaic switch based on lateral BiFeO3 cells

Sung

Lee

et al. 2013

NPG Asia Mater

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“…In a previous study, we found that n-type-doped area of BFO by control of oxygen vacancies reveal prominently lower electronic conduction when compared with p-type doping areas. 33 It is likely that La 3 þ ions substitute Bi 3 þ ions (A-site doping) because they have similar effective ionic radii (1.36 Å ). 34 Although the La substitutions would modify structural and ferroelectric properties such as domain size, coercive voltage and fatigue behavior, 35,36 in many cases only the La 5% substitutions do not cause dramatic changes in physical properties.…”

Section: Resultsmentioning

confidence: 99%

Electric control of straight stripe conductive mixed-phase nanostructures in La-doped BiFeO3

et al. 2014

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This study examines the atomic force microscope (AFM) tip-based electrical formation of tens of microns long stripe (and B100 nm wide) inorganic one-dimensional nanostructures based on the morphotropic phase boundary of La-doped BiFeO 3 epitaxial thin films. The substitution of Lanthanum into bismuth ferrite not only produces the formation of straight stripe mixedphase patterns but also improves the spatial continuity drastically by two orders of magnitude. We create, switch and erase stripe nanostructures in a reversible and deterministic way. We demonstrate that electrically formed areas with a nearly single variant alignment can be overwritten with different alignments repeatedly, which reflects the reversible and nonvolatile nature of the switching process. In addition, we explore the functionality of the created nanostructures by clarifying ferroelectric polarizations and observing the improvement of the electronic conduction at the phase boundary. Our findings provide new pathways to one-dimensional rewritable nanostructures and inspire researchers to conceive various multifunctional devices by combining the superb electromechanical property with their unique interfacial electronic conduction properties at nanoscale phase boundaries.

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“…Oxygen vacancies generated during the deposition of Ba 0.7 Sr 0.3 TiO 3 are likely the charge traps. 26 This effect should exist in most oxide-based MIM devices, though it may not be the dominating factor. Further investigation using planar MIM devices should lead to a better understanding of the resistive switching phenomona.…”

confidence: 99%

Charge trapping-detrapping induced resistive switching in Ba0.7Sr0.3TiO3

et al. 2012

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Intensive research has been devoted to the resistive switching phenomena observed in many transitional metal oxides because of its potential for non-volatile memory application. To clarify the underlying mechanism of resistive switching, a planar device can provide information that is not accessible in conventional vertical sandwich structures. Here we report the observation of resistive switching behavior in a Pt/Ba0.7Sr0.3TiO3/Pt planar device. Using in-situ scanning Kelvin probe microscopy, we demonstrate that charge trapping/detrapping around the Pt/Ba0.7Sr0.3TiO3 interface modulates the Schottky barrier, resulting in the observed resistive switching. The findings are valuable for the understanding of resistive switching in oxide materials

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Electric modulation of conduction in multiferroic Ca-doped BiFeO3 films

Cited by 497 publications

References 40 publications

Single ferroelectric-domain photovoltaic switch based on lateral BiFeO3 cells

Single ferroelectric-domain photovoltaic switch based on lateral BiFeO3 cells

Electric control of straight stripe conductive mixed-phase nanostructures in La-doped BiFeO3

Charge trapping-detrapping induced resistive switching in Ba0.7Sr0.3TiO3

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