Negative Spin Polarization and Large Tunneling Magnetoresistance in Epitaxial<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Co</mml:mi><mml:mo stretchy="false">|</mml:mo><mml:msub><mml:mi>SrTiO</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mo stretchy="false">|</mml:mo><mml:mi>Co</mml:mi></mml:math>Magnetic Tunnel Junctions

Velev, Julian P.; Belashchenko, Kirill D.; Stewart, Derek A.; Schilfgaarde, Mark van; Jaswal, S. S.; Tsymbal, Evgeny Y.

doi:10.1103/physrevlett.95.216601

Cited by 112 publications

(61 citation statements)

References 27 publications

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“…Due to the assumed RuO 2 / BaO interface termination, there are no induced magnetic moments on the interfacial Ti ions, as was found for other interfaces. 17,31 As is evident from Fig. 2, a small magnetic moment ͑about 0.02 B ͒ induced on the O atom within the interfacial BaO monolayer is only weakly influenced by polarization reversal.…”

mentioning

confidence: 65%

Magnetoelectric effect at the SrRuO3/BaTiO3 (001) interface: An ab initio study

Niranjan

Burton

Velev

et al. 2009

Applied Physics Letters

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115

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Ferromagnet/ferroelectric interface materials have emerged as structures with strong magnetoelectric coupling that may exist due to unconventional physical mechanisms. Here we present a first-principles study of the magnetoelectric effect at the ferromagnet/ferroelectric SrRuO3/BaTiO3 (001) interface. We find that the exchange splitting of the spin-polarized band structure, and therefore the magnetization, at the interface can be altered substantially by reversal of the ferroelectric polarization in the BaTiO3. These magnetoelectric effects originate from the screening of polarization charges at the SrRuO3/BaTiO3 interface and are consistent with the Stoner model for itinerant magnetism.

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mentioning

confidence: 65%

Magnetoelectric effect at the SrRuO3/BaTiO3 (001) interface: An ab initio study

Niranjan

Burton

Velev

et al. 2009

Applied Physics Letters

Self Cite

134

115

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“…In contrast, it is known that tunneling through insulators can be understood in terms of the evanescent states 17 and the method to investigate them is the complex band structure in the energy gap region. [18][19][20][21] So far, however, this approach has not been applied to spin-filter materials such as EuO. It has recently been shown, both theoretically using reliable GW calculations 22 and experimentally using angle-resolved photoemission experiments, 23 that the band gap in EuO is indirect, with the conduction-band minimum being located at the X point in the Brillouin zone.…”

Section: Introductionmentioning

confidence: 99%

Spin filtering with EuO: Insight from the complex band structure

et al. 2012

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Spin-filter tunneling is a promising way to create highly-spin-polarized currents. So far the understanding of the spin-filtering effect has been limited to a free-electron description based on the spin-dependent tunneling barrier height. In this work we explore the complex of EuO as a representative ferromagnetic insulator used in spin-filter tunneling experiments and show that the mechanism of spin filtering is more intricate than it has been previously thought. We demonstrate the importance of the multiorbital band structure with an indirect band gap for spin-filter tunneling. By analyzing the symmetry of the complex bands and the decay rates for different wave vectors and energies we draw conclusions about spin-filter efficiency of EuO. Our results provide guidelines for the design of spin-filter tunnel junctions with enhanced spin polarization.

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“…In the energy band regions, complex solutions for the band structure represent evanescent states rather than propagating Bloch states of a crystal. This approach has been efficiently used in the field of spin-polarized tunneling [18], where the CBS of the tunneling barrier material was found to have profound implications for tunneling magnetoresistance through symmetry filtering of the propagating states [19,20] and for spin filtering through the spin-dependent decay rate of the evanescent states [21]. In the case of TIs, the bulk evanescent states are expected to be intrinsically coupled to the topologically protected states.…”

Section: Introductionmentioning

confidence: 99%

Complex band structure of topologically protected edge states

et al. 2014

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One of the great successes of modern condensed matter physics is the discovery of topological insulators (TIs). A thorough investigation of their properties could bring such materials from fundamental research to potential applications. Here, we report on theoretical investigations of the complex band structure (CBS) of two-dimensional (2D) TIs. We utilize the tight-binding form of the Bernevig, Hughes, and Zhang model as a prototype for a generic 2D TI. Based on this model, we outline the conditions that the CBS must satisfy in order to guarantee the presence of topologically protected edge states. Furthermore, we use the Green's function technique to show how these edge states are localized, highlighting the fact that the decay of the edge-state wave functions into the bulk of a TI is not necessarily monotonic and, in fact, can exhibit an oscillatory behavior that is consistent with the predicted CBS of the bulk TI. These results may have implications for electronic and spin transport across a TI when it is used as a tunnel barrier.

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Negative Spin Polarization and Large Tunneling Magnetoresistance in EpitaxialCo|SrTiO3|CoMagnetic Tunnel Junctions

Cited by 112 publications

References 27 publications

Magnetoelectric effect at the SrRuO3/BaTiO3 (001) interface: An ab initio study

Magnetoelectric effect at the SrRuO3/BaTiO3 (001) interface: An ab initio study

Spin filtering with EuO: Insight from the complex band structure

Complex band structure of topologically protected edge states

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