High output voltage of magnetic tunnel junctions with a Cu(In0.8Ga0.2)Se2 semiconducting barrier with a low resistance–area product

Mukaiyama, Koki; Kasai, S.; Takahashi, Y. K.; Kondou, Kouta; Otani, Y.; Mitani, Seiji; Hono, K.

doi:10.7567/apex.10.013008

Cited by 11 publications

(5 citation statements)

References 15 publications

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“…Besides the TMR versus bias determined from the differential conductance, we have also analyzed a related parameter which is important for applications, namely the output voltage of the device, [ 21–24 ] defined as

\begin{matrix} Δ V = (||, V) \times \frac{R_{A P} - R_{P}}{R_{P}} \end{matrix}

…”

Section: Resultsmentioning

confidence: 99%

“…We report an electric‐bias‐induced two‐ to threefold increase of the TMR in hybrid MTJs (H‐MTJs) of V/MgO/Fe/MgO/Fe/Co (NS/I/F1/I/F2 with NS being a normal metal with surface states) in a wide temperature range, from liquid helium to room temperatures. The output voltage parameter, which is crucial for possible applications, [ 21–24 ] strongly exceeds the values observed for single barrier F1/I/F2 MTJs at biases above 0.5 V. Moreover, to our best knowledge, the room temperature value exceeding 0.8 V are a record high for all known spintronic devices. We explain this unprecedented behavior with a simplified model, considering magnetic‐state‐dependent sequential tunneling though two nonlinear devices in series.…”

Section: Introductionmentioning

confidence: 99%

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Boosting Room Temperature Tunnel Magnetoresistance in Hybrid Magnetic Tunnel Junctions Under Electric Bias

González-Ruano

Tiuşan

Hehn

et al. 2021

Adv Elect Materials

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Spin‐resolved electron symmetry filtering is a key mechanism behind giant tunneling magnetoresistance (TMR) in Fe/MgO/Fe and similar magnetic tunnel junctions (MTJs), providing room temperature functionality in spin electronics. However, the electron symmetry filtering breaks down under applied bias, dramatically reducing the TMR above 0.5 V. This strongly hampers the application range of MTJs. To circumvent the problem, resonant tunneling through quantum well states in thin layers has been used so far. This mechanism, however, is mainly effective at low temperatures. Here, a fundamentally different approach is demonstrated, providing a strong TMR boost under applied bias in V/MgO/Fe/MgO/Fe/Co hybrids. This pathway uses spin orbit coupling (SOC) controlled interfacial states in vanadium, which contrary to the V(001) bulk states are allowed to tunnel to Fe(001) at low biases. The experimentally observed strong increase of TMR with bias is modeled using two nonlinear resistances in series, with the low bias conductance of the first (V/MgO/Fe) element being boosted by the SOC‐controlled interfacial states, while the conductance of the second (Fe/MgO/Fe) junctions are controlled by the relative alignment of the ferromagnetic layers. These results pave a way to unexplored and fundamentally different spintronic device schemes, with tunneling magnetoresistance uplifted under applied electric bias.

show abstract

\begin{matrix} Δ V = (||, V) \times \frac{R_{A P} - R_{P}}{R_{P}} \end{matrix}

…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Boosting Room Temperature Tunnel Magnetoresistance in Hybrid Magnetic Tunnel Junctions Under Electric Bias

González-Ruano

Tiuşan

Hehn

et al. 2021

Adv Elect Materials

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show abstract

“…We report an electric-bias-induced 2-3 fold increase of the TMR in hybrid MTJs (H-MTJs) of V/MgO/Fe/MgO/Fe/Co (NS/I/F1/I/F2 with NS being a normal metal with surface states) in a wide temper- ature range, from liquid helium to room temperatures. The output voltage parameter, which is crucial for possible applications [21][22][23][24] , strongly exceeds the values observed for single barrier F1/I/F2 MTJs at biases above 0.5 V. Moreover, to our best knowledge, the room temperature value exceeding 0.8 V are a record high for all known spintronic devices. We explain this unprecedented behavior with a simplified model, considering magneticstate-dependent sequential tunneling though two nonlinear devices in series.…”

Section: Introductionmentioning

confidence: 71%

“…Besides the TMR vs bias determined from the differential conductance, we have also analyzed a related parameter which is important for applications, namely the output voltage of the device [21][22][23][24] , defined as…”

Section: B Bias Dependence Of Output Voltagementioning

confidence: 99%

Boosting room temperature tunnel magnetoresistance in hybrid magnetic tunnel junctions under electric bias

González-Ruano¹,

Tiuşan²,

Hehn³

et al. 2021

Preprint

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Spin-resolved electron symmetry filtering is a key mechanism behind giant tunneling magnetoresistance (TMR) in Fe/MgO/Fe and similar magnetic tunnel junctions (MTJs), providing room temperature functionality in modern spin electronics. However, the core process of the electron symmetry filtering breaks down under applied bias, dramatically reducing the TMR above 0.5 V. This strongly hampers the application range of MTJs. To circumvent the problem, resonant tunneling between ferromagnetic electrodes through quantum well states in thin layers has been used so far. This mechanism, however, is mainly effective at low temperatures. Here, a fundamentally different approach is demonstrated, providing a strong TMR boost under applied bias in V/MgO/Fe/MgO/Fe/Co hybrids. This pathway uses spin orbit coupling (SOC) controlled interfacial states in vanadium, which contrary to the V(001) bulk states are allowed to tunnel to Fe(001) at low biases. The experimentally observed strong increase of TMR with bias is modelled using two nonlinear resistances in series, with the low bias conductance of the first (V/MgO/Fe) element being boosted by the SOC-controlled interfacial states, while the conductance of the second (Fe/MgO/Fe) junctions controlled by the relative alignment of the two ferromagnetic layers. These results pave a way to unexplored and fundamentally different spintronic device schemes, with tunneling magnetoresistance uplifted under applied electric bias.

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“…Such high MR output was explained theoretically as a result of the spindependent coherent tunneling of ∆ 1 wave functions [20]. In a more recent study, Mukaiyama et al demonstrated large voltage outputs under bias voltages, which indicated that the CIGS-based MTJ is particularly attractive for read-head applications [21]. To consider potential applications to STT-MRAM cells, the possibility of obtaining large PMA on CIGS-based MTJs must be investigated; however, no experimental and theoretical studies have been done on this issue.…”

Section: Introductionmentioning

confidence: 99%

Giant interfacial perpendicular magnetic anisotropy in Fe/CuIn$_{1-x}$Ga$_x$Se$_2$ beyond Fe/MgO

Masuda,

Kasai,

Miura

et al. 2017

Preprint

Self Cite

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We study interfacial magnetocrystalline anisotropies in various Fe/semiconductor heterostructures by means of first-principles calculations. We find that many of those systems show perpendicular magnetic anisotropy (PMA) with a positive value of the interfacial anisotropy constant Ki. In particular, the Fe/CuInSe2 interface has a large Ki of ∼ 2.3 mJ/m 2 , which is about 1.6 times larger than that of Fe/MgO known as a typical system with relatively large PMA. We also find that the values of Ki in almost all the systems studied in this work follow the well-known Bruno's relation, which indicates that minority-spin states around the Fermi level provide dominant contributions to the interfacial magnetocrystalline anisotropies. Detailed analyses of the local density of states and wave-vector-resolved anisotropy energy clarify that the large Ki in Fe/CuInSe2 is attributed to the preferable 3d-orbital configurations around the Fermi level in the minority-spin states of the interfacial Fe atoms. Moreover, we have shown that the locations of interfacial Se atoms are the key for such orbital configurations of the interfacial Fe atoms.

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High output voltage of magnetic tunnel junctions with a Cu(In_0.8Ga_0.2)Se₂ semiconducting barrier with a low resistance–area product

Cited by 11 publications

References 15 publications

Boosting Room Temperature Tunnel Magnetoresistance in Hybrid Magnetic Tunnel Junctions Under Electric Bias

Boosting Room Temperature Tunnel Magnetoresistance in Hybrid Magnetic Tunnel Junctions Under Electric Bias

Boosting room temperature tunnel magnetoresistance in hybrid magnetic tunnel junctions under electric bias

Giant interfacial perpendicular magnetic anisotropy in Fe/CuIn$_{1-x}$Ga$_x$Se$_2$ beyond Fe/MgO

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