Spin-dependent tunneling through high-k LaAlO3

Garcia, Vincent; Bibès, Manuel; Maurice, Jean‐Luc; Jacquet, Éric; Bouzéhouane, K.; Contour, Jp; Barthélémy, Alain

doi:10.1063/1.2132526

Cited by 27 publications

(23 citation statements)

References 26 publications

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“…Although for sp-bonded insulators the s-like states have the lowest rate of decay there are some cases like TiO 2 , SrTiO 3 , and other transition metal oxides in which the complex band structure of the insulator has multiple evanescent states with comparable rates of decay that allow efficient tunneling of the d states from the electrodes [123]. Negative spin polarization was observed for the Co/SrTiO 3 [124], Co/TiO 2 [125] and Co/LaAlO 3 interfaces [126]. For the former two interfaces the negative spin polarization is due to the Ti 3d states which have a large density in the minority-spin channel at the Fermi energy, whereas for the latter interface it is probably due to tunneling through the La 4d states [127].…”

Section: Relation To Transportmentioning

confidence: 97%

Interface effects in spin-polarized metal/insulator layered structures

Velev

Dowben

Tsymbal

et al. 2008

Surface Science Reports

113

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Recent advances in thin-film deposition techniques, such as molecular beam epitaxy and pulsed laser deposition, have allowed for the manufacture of heterostructures with nearly atomically abrupt interfaces. Although the bulk properties of the individual heterostructure components may be well-known, often the heterostructures exhibit novel and sometimes unexpected properties due to interface effects. At heterostructure interfaces, lattice structure, stoichiometry, interface electronic structure (bonding, interface states, etc.), and symmetry all conspire to produce behavior different from the bulk constituents. This review discusses why knowledge of the electronic structure and composition at the interfaces is pivotal to the understanding of the properties of heterostructures, particularly the (spin polarized) electronic transport in (magnetic) tunnel junctions.

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Section: Relation To Transportmentioning

confidence: 97%

Interface effects in spin-polarized metal/insulator layered structures

Velev

Dowben

Tsymbal

et al. 2008

Surface Science Reports

113

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“…[3][4][5][6][7][8][9][10] Interfaces with other oxides of interest, such as LaAlO 3 (LAO) or MgO, have been less investigated. [11][12][13] Several studies conducted to analyze the properties of ultrathin manganite films on top of various substrates indicate a severe degradation of the magnetotransport properties below a critical thickness. 14,15 The origin of this degradation has usually been attributed to the existence of phase segregation and disorder at the nanoscale motivated mainly by structural strain, oxygen stoichiometry, and variations of the chemical composition.…”

Section: Introductionmentioning

confidence: 99%

Interfacial effects in manganite thin films with different capping layers of interest for spintronic applications

et al. 2011

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We report on the use of surface-sensitive techniques (x-ray absorption spectroscopy and x-ray magnetic circular dichroism) to investigate interfacial effects in sputtered manganite thin films, La 2/3 Ca 1/3 MnO 3 (LCMO) and La 2/3 Sr 1/3 MnO 3 (LSMO), with different capping layers [MgO, LaAlO 3 (LAO), SrTiO 3 (STO), NdGaO 3 (NGO), and Au]. To ensure surface sensitivity, data were acquired by using the total electron yield detection mode. It is found that LSMO and LCMO films exhibit similar behavior when capped with oxide layers but dissimilar effects when a metallic capping is used. Almost bulklike Mn valence at the interface was observed in the case of LAO capping. However, a notorious increase of the Mn oxidation state was detected for both MgO and NGO capping layers. In contrast, metallic Au and STO capping promotes a reduction of the Mn oxidation state. These results are correlated with the x-ray magnetic circular dichroism data, showing a concomitant decrease of the saturation magnetization at the interface in those cases where a modification of the Mn oxidation state is observed.

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“…For the LAO-Co interface, g was measured by Garcia et al [35] in LSMO-LAO-Co magnetic tunnel junctions showing negative tunnel magnetoresistance of about −20 per cent at low temperature. Using Julliere's formula [36] and a spin polarization of +90 per cent for LSMO [37], one estimates g = −0.1.…”

Section: Conditions For Spin Injectionmentioning

confidence: 99%

Towards electrical spin injection into LaAlO ₃ –SrTiO ₃

Bibès

Reyren

Lesne

et al. 2012

Phil. Trans. R. Soc. A.

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Future spintronics devices will be built from elemental blocks allowing the electrical injection, propagation, manipulation and detection of spin-based information. Owing to their remarkable multi-functional and strongly correlated character, oxide materials already provide such building blocks for charge-based devices such as ferroelectric fieldeffect transistors (FETs), as well as for spin-based two-terminal devices such as magnetic tunnel junctions, with giant responses in both cases. Until now, the lack of suitable channel materials and the uncertainty of spin-injection conditions in these compounds had however prevented the exploration of similar giant responses in oxide-based lateral spin transport structures. In this paper, we discuss the potential of oxide-based spin FETs and report magnetotransport data that suggest electrical spin injection into the LaAlO 3 -SrTiO 3 interface system. In a local, three-terminal measurement scheme, we analyse the voltage variation associated with the precession of the injected spin accumulation driven by perpendicular or longitudinal magnetic fields (Hanle and 'inverted' Hanle effects). The spin accumulation signal appears to be much larger than expected, probably owing to amplification effects by resonant tunnelling through localized states in the LaAlO 3 . We give perspectives on how to achieve direct spin injection with increased detection efficiency, as well on the implementation of efficient top gating schemes for spin manipulation.

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Spin-dependent tunneling through high-k LaAlO3

Abstract: We report on the use of the LaAlO 3 (LAO) high-k dielectric as a tunnel barrier in magnetic tunnel junctions. From tunnel magnetoresistance (TMR) measurements on epitaxial

Cited by 27 publications

References 26 publications

Interface effects in spin-polarized metal/insulator layered structures

Interface effects in spin-polarized metal/insulator layered structures

Interfacial effects in manganite thin films with different capping layers of interest for spintronic applications

Towards electrical spin injection into LaAlO ₃ –SrTiO ₃

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Spin-dependent tunneling through high-k LaAlO3

Abstract: We report on the use of the LaAlO 3 (LAO) high-k dielectric as a tunnel barrier in magnetic tunnel junctions. From tunnel magnetoresistance (TMR) measurements on epitaxial

Cited by 27 publications

References 26 publications

Interface effects in spin-polarized metal/insulator layered structures

Interface effects in spin-polarized metal/insulator layered structures

Interfacial effects in manganite thin films with different capping layers of interest for spintronic applications

Towards electrical spin injection into LaAlO 3 –SrTiO 3

Contact Info

Product

Resources

About

Towards electrical spin injection into LaAlO ₃ –SrTiO ₃