Quenching of Magnetoresistance by Hot Electrons in Magnetic Tunnel Junctions

Zhang, S.; Levy, Peter M.; Marley, A. C.; Parkin, S. S. P.

doi:10.1103/physrevlett.79.3744

Cited by 529 publications

(418 citation statements)

References 17 publications

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“…This feature is common in magnetic tunnel junctions 24 ͑MTJs͒ and ascribed in large part to magnon excitations at the electrode-barrier interfaces. 25 This mechanism is certainly also active here on the LSMO interface, but, since only one of the electrodes is magnetic, it cannot account for an approximately equal drop in positive and negative bias. A symmetric drop can only be due to magnon excitations inside the BMO barrier.…”

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confidence: 99%

Spin filtering through ferromagneticBiMnO3tunnel barriers

et al. 2005

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We report on experiments of spin filtering through ultrathin single-crystal layers of the insulating and ferromagnetic oxide BiMnO 3 ͑BMO͒. The spin polarization of the electrons tunneling from a gold electrode through BMO is analyzed with a counterelectrode of the half-metallic oxide La 2/3 Sr 1/3 MnO 3 ͑LSMO͒. At 3 K we find a 50% change of the tunnel resistances according to whether the magnetizations of BMO and LSMO are parallel or opposite. This effect corresponds to a spin-filtering efficiency of up to 22%. Our results thus show the potential of complex ferromagnetic insulating oxides for spin filtering and injection.

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confidence: 99%

Spin filtering through ferromagneticBiMnO3tunnel barriers

et al. 2005

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“…Yet tunnelling magnetoresistance ratios (TMRs) remain one order of magnitude below those predicted 17 . The impact of intrinsic effects such as magnon and phonon generation on TMR has been documented 18,19 . On the other hand, the impact of structural defects in MgO on tunnelling is only emerging in this otherwise widely studied, canonical spintronic system [20][21][22][23][24][25][26] .…”

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Localized states in advanced dielectrics from the vantage of spin- and symmetry-polarized tunnelling across MgO

et al. 2014

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Research on advanced materials such as multiferroic perovskites underscores promising applications, yet studies on these materials rarely address the impact of defects on the nominally expected materials property. Here, we revisit the comparatively simple oxide MgO as the model material system for spin-polarized solid-state tunnelling studies. We present a defect-mediated tunnelling potential landscape of localized states owing to explicitly identified defect species, against which we examine the bias and temperature dependence of magnetotransport. By mixing symmetry-resolved transport channels, a localized state may alter the effective barrier height for symmetry-resolved charge carriers, such that tunnelling magnetoresistance decreases most with increasing temperature when that state is addressed electrically. Thermal excitation promotes an occupancy switchover from the ground to the excited state of a defect, which impacts these magnetotransport characteristics. We thus resolve contradictions between experiment and theory in this otherwise canonical spintronics system, and propose a new perspective on defects in dielectrics.

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“…An important device merit is the TMR ratio and much theoretical and experimental efforts have been devoted to create MTJs with different ferromagnetic metals and insulating materials in order to generate a large ratio. While materials such as MgO and Al 2 O 3 are the most popular barrier materials in practical MTJs, [16][17][18][19][20] 2D materials graphene 21,22 and transition-metal dichalcogenides 23,24 have also been investigated in this context.…”

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Nonequilibrium spin injection in monolayer black phosphorus

Chen

Wang

et al. 2016

Phys. Chem. Chem. Phys.

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Monolayer black phosphorus (MBP) is an interesting emerging electronic material with a direct band gap and relatively high carrier mobility. In this work we report a theoretical investigation of nonequilibrium spin injection and spin-polarized quantum transport in MBP from ferromagnetic Ni contacts, in two-dimensional magnetic tunneling structures. We investigate physical properties of the spin injection efficiency, the tunnel magnetoresistance ratio, spin-polarized currents, charge currents and transmission coefficients as a function of external bias voltage, for two different device contact structures where MBP is contacted by Ni(111) and by Ni(100). While both structures are predicted to give respectable spin-polarized quantum transport, the Ni(100)/MBP/Ni(100) trilayer has the superior property where the spin injection and magnetoresistance ratio maintains almost a constant value against the bias voltage. The nonequilibrium quantum transport phenomenon is understood by analyzing the transmission spectrum at nonequilibrium. PACS numbers: 72.25.Mk, 73.43.Qt Two dimensional (2D) materials have received extensive investigations in recent years for possible applications in logic devices, photonic systems, solar cells, transparent substrates and perhaps most interestingly, flexible and wearable consumer electronics. 1 The thin layer of 2D material makes it a natural choice for producing flexible structures due to their out of plane flexibility. Many 2D materials have strong covalent bonds and diverse electronic structures -properties which are needed for reliable and durable applications.So far, several 2D materials have been fabricated successfully including the celebrated graphene, 2-5 various 2D transition-metal dichalcogenides, 6-8 and the monolayer black phosphorus (MBP). [9][10][11][12][13] In particular, as one of the newest members of 2D material family, MBP is very interesting in several aspects. First, different from transition-metal dichalcogenides, black phosphorus is made of a single atomic specie, phosphorus. Second, different from graphene, the phosphorus atoms in MBP are not all located in a plane but form a buckled hexagonal structure by covalence bonds and few-layer black phosphorus has an ideal direct bandgap, a property that is very important for optoelectronics. Third, MBP has an intrinsic band gap and graphene does not. Though lower than that of graphene, few-layer black phosphorus has respectable mobilities of ∼ 1000cm 2 V −1 s −1 as reported experimentally. 9 While the materials properties make MBP very interesting and potentially important for emerging flexible electronics, another critical issue is to achieve low power operation. In this regard, one notes that the energy scale of spin dynamics is typically many orders of magnitude smaller than that of charge dynamics, and low power electronics operation can thus be achieved in spintronics devices whose operation principle is based on spin dynamics. 14,15 Existing and well studied spintronic systems include magnetic random access memory...

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Quenching of Magnetoresistance by Hot Electrons in Magnetic Tunnel Junctions

Cited by 529 publications

References 17 publications

Spin filtering through ferromagneticBiMnO3tunnel barriers

Spin filtering through ferromagneticBiMnO3tunnel barriers

Localized states in advanced dielectrics from the vantage of spin- and symmetry-polarized tunnelling across MgO

Nonequilibrium spin injection in monolayer black phosphorus

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