Enhanced tunnelling electroresistance effect due to a ferroelectrically induced phase transition at a magnetic complex oxide interface

Yin, Yuewei; Burton, John; Kim, Young Min; Borisevich, Albina Y.; Pennycook, Stephen J.; Yang, Sang Mo; Noh, T. W.; Gruverman, Alexei; Li, X. G.; Tsymbal, Evgeny Y.; Li, Qi

doi:10.1038/nmat3564

Cited by 297 publications

(276 citation statements)

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“…12,13 Up to recently, most studies of FTJs have focused on improving device performance by modifying the electrode materials. [14][15][16][17][18][19][20] Typical examples include the use of lightly doped semiconductors, [14][15][16] For a thick barrier, these obstacles can be avoided, but the tunneling current becomes too small for realizing a practically useful device. As an alternative, several groups have theoretically proposed a new kind of FTJ using an FE/paraelectric (FE/PE) composite barrier.…”

Section: Introductionmentioning

confidence: 99%

Overcoming the Fundamental Barrier Thickness Limits of Ferroelectric Tunnel Junctions through BaTiO₃/SrTiO₃ Composite Barriers

et al. 2016

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ABSTRACT:Ferroelectric tunnel junctions (FTJs) have attracted increasing research interest as a promising candidate for non-volatile memories. Recently, significant enhancements of tunneling electroresistance (TER) have been realized through modifications of electrode materials.However, direct control of the FTJ performance through modifying the tunneling barrier has not been adequately explored. Here, adding a new direction to FTJ research, we fabricated FTJs with Ferroelectric tunnel junctions (FTJs), composed of a thin ferroelectric (FE) layer sandwiched in between two metallic electrodes, have been intensively investigated in recent years. This device is considered to be a promising candidate for next-generation nonvolatile memories, because it combines the advantages of both ferroelectric random-access-memory and resistiveswitching memory. 1-3 The concept of FTJ was first proposed by Esaki in 1971, 4 but the research activities have not flourished untixl this decade. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] The operation of FTJs has been mainly explained in terms of interfacial screening of polarization charges. [5][6][7][8] In a metal 1(M1)/FE/metal 2 (M2) structured FTJ (Figure 1a), the two asymmetric electrodes lead to unequal screen lengths and potential changes at metal/FE interfaces. Depending on the polarizations, the electrostatic potential profile of tunneling barrier will be varied. As a result, the tunneling resistance can be switched between low (ON) and high (OFF) values by polarization reversal, leading to the socalled tunneling electroresistance (TER) effect.Extensive experimental works based on this asymmetric screening scenario have been reported during the last decade. In 2009, the TER effect was first demonstrated using conducting atomic force microscopy (CAFM). 9-11 Subsequently, FTJs with highly reproducible performance were realized in capacitor geometry, which will be useful for practical applications. 12,13 Up to recently, most studies of FTJs have focused on improving device performance by modifying the electrode materials. [14][15][16][17][18][19][20] Typical examples include the use of lightly doped semiconductors, [14][15][16] For a thick barrier, these obstacles can be avoided, but the tunneling current becomes too small for realizing a practically useful device. As an alternative, several groups have theoretically proposed a new kind of FTJ using an FE/paraelectric (FE/PE) composite barrier. 27,28 The PE layer provides a new route to control the tunneling barrier potentials, and thus the TER can be tuned and significantly enhanced. However, there have been few experimental efforts to systematically attest this theoretical prediction. 29 In this paper, we report experimental control of the TER effect by directly manipulating the tunneling barrier thickness and composition. For this purpose, we fabricated two types of FTJs: Figure S5), which further confirm good epitaxial film qualities.We estimated the lattice constants of the oxide layers from XRD reci...

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Section: Introductionmentioning

confidence: 99%

Overcoming the Fundamental Barrier Thickness Limits of Ferroelectric Tunnel Junctions through BaTiO₃/SrTiO₃ Composite Barriers

et al. 2016

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“…19 and references therein). Fully epitaxial junctions 20,21 are based on ferroelectric tunnel barriers made of highly strained perovskite oxide layers (e.g., BaTiO 3 , (Pb, Zr)TiO 3 , and BiFeO 3 ) associated to strongly correlated oxides (e.g., Nb:SrTiO 3 , (La,Sr)MnO 3 , (La,Ca)MnO 3 , and (Ca,Ce)MnO 3 ). The TER in such systems is convoluted with strong electric-field-induced modifications of the interfacial electronic properties making the understanding of the interplay between tunneling and polarization challenging.…”

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confidence: 99%

Engineering ferroelectric tunnel junctions through potential profile shaping

et al. 2015

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We explore the influence of the top electrode materials (W, Co, Ni, Ir) on the electronic band profile in ferroelectric tunnel junctions based on super-tetragonal BiFeO3. Large variations of the transport properties are observed at room temperature. In particular, the analysis of current vs. voltage curves by a direct tunneling model indicates that the metal/ferroelectric interfacial barrier height increases with the top-electrode work function. While larger metal work functions result in larger OFF/ON ratios, they also produce a large internal electric field which results in large and potentially destructive switching voltages.

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“…[1][2][3][4][5][6][7] Due to recent advances in atomic level synthesis technique, interface engineering [8][9][10][11][12][13] of oxides has emerged as a useful approach to explore and fine tune their functional properties. Because manipulating the interface is often associated with the added structural distortions, it is crucial to understand how the interfacial modification affects not only the structural but also the physical properties of entire constituent oxide layers.…”

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confidence: 99%

Research Update: Interface-engineered oxygen octahedral tilts in perovskite oxide heterostructures

et al. 2015

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Interface engineering of structural distortions is a key for exploring the functional properties of oxide heterostructures and superlattices. In this paper, we report on our comprehensive investigations of oxygen octahedral distortions at the heterointerface between perovskite oxides SrRuO3 and BaTiO3 on GdScO3 substrates and of the influences of the interfacially engineered distortions on the magneto-transport properties of the SrRuO3 layer. Our state-of-the-art annular bright-field imaging in aberration-corrected scanning transmission electron microscopy revealed that the RuO6 octahedral distortions in the SrRuO3 layer have strong dependence on the stacking order of the SrRuO3 and BaTiO3 layers on the substrate. This can be attributed to the difference in the interfacial octahedral connections. We also found that the stacking order of the oxide layers has a strong impact on the magneto-transport properties, allowing for control of the magnetic anisotropy of the SrRuO3 layer through interface engineering. Our results demonstrate the significance of the interface engineering of the octahedral distortions on the structural and physical properties of perovskite oxides.

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Enhanced tunnelling electroresistance effect due to a ferroelectrically induced phase transition at a magnetic complex oxide interface

Cited by 297 publications

References 30 publications

Overcoming the Fundamental Barrier Thickness Limits of Ferroelectric Tunnel Junctions through BaTiO₃/SrTiO₃ Composite Barriers

Overcoming the Fundamental Barrier Thickness Limits of Ferroelectric Tunnel Junctions through BaTiO₃/SrTiO₃ Composite Barriers

Engineering ferroelectric tunnel junctions through potential profile shaping

Research Update: Interface-engineered oxygen octahedral tilts in perovskite oxide heterostructures

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Enhanced tunnelling electroresistance effect due to a ferroelectrically induced phase transition at a magnetic complex oxide interface

Cited by 297 publications

References 30 publications

Overcoming the Fundamental Barrier Thickness Limits of Ferroelectric Tunnel Junctions through BaTiO3/SrTiO3 Composite Barriers

Overcoming the Fundamental Barrier Thickness Limits of Ferroelectric Tunnel Junctions through BaTiO3/SrTiO3 Composite Barriers

Engineering ferroelectric tunnel junctions through potential profile shaping

Research Update: Interface-engineered oxygen octahedral tilts in perovskite oxide heterostructures

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Product

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Overcoming the Fundamental Barrier Thickness Limits of Ferroelectric Tunnel Junctions through BaTiO₃/SrTiO₃ Composite Barriers

Overcoming the Fundamental Barrier Thickness Limits of Ferroelectric Tunnel Junctions through BaTiO₃/SrTiO₃ Composite Barriers