Effects of B and C doping on tunneling magnetoresistance in CoFe/MgO magnetic tunnel junctions

Chen, Andy Paul; Burton, John; Tsymbal, Evgeny Y.; Feng, Yuan Ping; Chen, Jingsheng

doi:10.1103/physrevb.98.045129

Cited by 11 publications

(6 citation statements)

References 39 publications

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“…[53,66,93,110,111,113,141,155] Figure 12a-d shows the possible defects inside junctions. [2] Although the role of defects has been investigated in detail in the context of, for instance, tunnel magnetoresistance [156][157][158] and perovskite solar cells, [159,160] how such defects affect the electrical characteristics of molecular junctions has only been occasionally studied. [93,[110][111][112][113][161][162][163] Line "B" corresponds to the "long" time of ≈2.5 min, measured at low frequency (f = 10 Hz).…”

Section: Role Of Defects and Self-repair Of Samsmentioning

confidence: 99%

The Unusual Dielectric Response of Large Area Molecular Tunnel Junctions Probed with Impedance Spectroscopy

Chen

Nijhuis

2021

Adv Elect Materials

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workings of charge transport in exquisite detail in areas including molecular plasmonics, [9] spintronics, [10,11] bioelectronics, [12] sensing, [13] catalysis, [14,15] energy storage, [12,16] memory, [17][18][19] and flexible electronics. [2,3,[20][21][22] Control over the dielectric behavior of nanoscale systems is important for a wide range of applications including supercapacitors, [23] organic field effect transistors (OFETs), [24][25][26][27] flexible and stretchable electronics, [25,28] optoelectronics, [29] and memory. [30] For example, for OFETs, it is important to develop gate materials with high dielectric constants yet with low leakage (via tunneling) currents. [24,25] In principle, molecular junctions are interesting because they allow us to study the dielectric properties of materials at the molecular length scale, but their dielectric behavior remains, to date, virtually unexplored despite promising features. [31][32][33][34] For instance, it has been predicted that, due to their well-organized nature, self-assembled monolayers (SAMs) can have very high relative dielectric constants ε r of ≈20, [32] while usually bulk organic materials have values of ε r in the range of 2-4. [35,36] Theoretically it has been shown that ε r can increase with the thickness of SAMs helping to avoid the adverse decrease of the capacitance in OFETSs with increasing gate dielectric thickness [26,31,34,35] which, in turn, can be used to reduce leakage currents. The dielectric behavior of SAMs are also important to modulate work functions, [37][38][39][40] or to reduceThe dielectric behavior of organic materials at molecular dimensions can be vastly different than their bulk counterparts and therefore it is important to investigate and control the dielectric response of molecular-scale materials for a large variety of applications. Large-area molecular junctions are explored to study the charge transport mechanisms with unprecedented detail and to demonstrate novel functionalities. Therefore, large-area molecular junctions are, in principle, a promising platform to study the dielectric effects at the molecular scale. This review summarizes recent progress on the measurements and understanding of the dielectric behavior of molecular systems and how they behave differently from their bulk properties. This review introduces, briefly, the concepts of impedance spectroscopy (IS) and how this technique can be applied to study the dielectric response of solid-state large-area molecular junctions. This analysis gives new insights in the factors that determine the dielectric constant of monolayers (including collective electrostatic effects and how the dielectric constant increases with monolayer thickness), how IS gives new insights into the role of defects, and the factors that contribute to the molecule-electrode contact resistance. This review ends with an outlook highlighting interesting future directions.

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Section: Role Of Defects and Self-repair Of Samsmentioning

confidence: 99%

The Unusual Dielectric Response of Large Area Molecular Tunnel Junctions Probed with Impedance Spectroscopy

Chen

Nijhuis

2021

Adv Elect Materials

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“…Variation in the fabrication process directly leads to variability in critical device parameters, notably the threshold current I th and the MTJ resistances, which are functions of the device dimensions. Additionally, device parameters, such as the TMR, may be variably reduced on device-by-device basis due to defects, in particular the migration of B atoms to the CoFe/MgO interface [39]. Fig.…”

Section: Sensitivity To Device Variabilitymentioning

confidence: 99%

Energy and Performance Benchmarking of a Domain Wall-Magnetic Tunnel Junction Multibit Adder

Xiao

Marinella

Bennett

et al. 2019

IEEE J. Explor. Solid-State Comput. Devices Circuits

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The domain-wall (DW)-magnetic tunnel junction (MTJ) device implements universal Boolean logic in a manner that is naturally compact and cascadable. However, an evaluation of the energy efficiency of this emerging technology for standard logic applications is still lacking. In this article, we use a previously developed compact model to construct and benchmark a 32-bit adder entirely from DW-MTJ devices that communicates with DW-MTJ registers. The results of this large-scale design and simulation indicate that while the energy cost of systems driven by spin-transfer torque (STT) DW motion is significantly higher than previously predicted, the same concept using spin-orbit torque (SOT) switching benefits from an improvement in the energy per operation by multiple orders of magnitude, attaining competitive energy values relative to a comparable CMOS subprocessor component. This result clarifies the path toward practical implementations of an all-magnetic processor system. INDEX TERMS Benchmarking, domain wall (DW), magnetic logic, magnetic tunnel junction (MTJ), post-CMOS logic, spintronics.

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“…We believe the high interfacial perpendicular anisotropy of CoFeC and its good thermal tolerance are attributed to the dif ferent thermal dynamic diffusion behavior of C and B during the annealing. A first principle calculation has been done for the two systems [26], which shows B favors substitution and C favors the interstitial site. As a result, it can be expected the MgO/CoFeC system provides better thermal tolerance and larger interfacial anisotropy than those in MgO/CoFeB system, since there will be more orbital hybridization of Fe3d (and/or Co3d) and O2p formed at MgO/CoFeC inter face than MgO/CoFeB interface [5,21].…”

Section: Figures 1(a)-(d) Show Polarmoke Hysteresis Loops Ofmentioning

confidence: 99%

Ferromagnetic alloy material CoFeC with high thermal tolerance in MgO/CoFeC/Pt structure and comparable intrinsic damping factor with CoFeB

Chen

Zhou

Lin

et al. 2018

J. Phys. D: Appl. Phys.

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The thermal tolerance and perpendicular magnetic anisotropy (PMA) of ferromagnetic alloy Co 40 Fe 40 C 20 in the structure MgO/CoFeC/Pt (or Ta) were investigated and compared with the commonly used CoFeB alloy. It is found that the PMA of CoFeC with K i,CoFeC = 2.21 erg cm −2 , which is 59% higher than that of CoFeB, can be obtained after proper postannealing treatment. Furthermore, CoFeC alloy provides better thermal tolerance to temperature of 400 °C than CoFeB. The studies on ferromagnetic resonance show that the intrinsic damping constant α in of Co 40 Fe 40 C 20 alloy is 0.0047, which is similar to the reported value of 0.004 for Co 40 Fe 40 B 20 alloy. The comprehensive comparisons indicate that CoFeC alloy is a promising candidate for the application of the integration of spin torque transfer magnetic random access memory with complementary metaloxide semiconductor processes.

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Effects of B and C doping on tunneling magnetoresistance in CoFe/MgO magnetic tunnel junctions

Cited by 11 publications

References 39 publications

The Unusual Dielectric Response of Large Area Molecular Tunnel Junctions Probed with Impedance Spectroscopy

The Unusual Dielectric Response of Large Area Molecular Tunnel Junctions Probed with Impedance Spectroscopy

Energy and Performance Benchmarking of a Domain Wall-Magnetic Tunnel Junction Multibit Adder

Ferromagnetic alloy material CoFeC with high thermal tolerance in MgO/CoFeC/Pt structure and comparable intrinsic damping factor with CoFeB

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