Effect of Annealing and Barrier Thickness on MgO-Based Co/Pt and Co/Pd Multilayered Perpendicular Magnetic Tunnel Junctions

Ye, Li-Xiu; Lee, Ching‐Ming; Syu, Jhin-Wei; Wang, Yi-Rung; Lin, Kun-Wei; Chang, Yu-Hsiu; Wu, Te‐Ho

doi:10.1109/tmag.2008.2001648

Cited by 21 publications

(6 citation statements)

References 13 publications

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“…Abundant published works have been reported on the interface effects of the FM=AF bilayers caused by the MFA process. 4,10,[12][13][14][15][16][17][18][19][20][21] An extended interfacial region in metal=NiO systems after annealing was exhibited due to the chemical reaction and diffusion at the interface. 10) The interface features are closely related to the interface spin configuration and thus have a considerable impact on the magnetic properties of the FM=AF bilayers.…”

Section: Introductionmentioning

confidence: 99%

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Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co₉₀Fe₁₀bilayers

Zheng

Chiu

et al. 2017

Jpn. J. Appl. Phys.

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The ferromagnetic (FM)/antiferromagnetic (AF) bilayer structures have drawn intensive attention because of their wide applications in modern spintronic devices. While abundant published works have been reported on the interface effects of the FM/AF bilayers caused by the magnetic field annealing (MFA) process, the volume effects caused by the MFA treatment have been rarely considered. In this work, the microstructural and magnetic properties of the NiO/CoFe bilayers with various CoFe thicknesses were investigated under different annealing temperatures. At high annealing temperature, the interlayer mixing and exchange coupling between NiO and CoFe layers were promoted and consequently the interface effects were facilitated. The interfacial oxides acted as pinning centers and randomly pinned the FM domains, leading to an increase of coercivity and a considerable degradation of uniaxial anisotropy. The increase of coercivity was also contributed by the enhancement of the interfacial exchange coupling between the NiO and CoFe layers after MFA. As the CoFe thickness increased, the volume effects tended to dominate over the interface effects, resulting in the preservation the uniaxially anisotropic features of CoFe. These results indicate that both the coercivity and anisotropic features of the NiO/CoFe bilayers can be directly affected by the MFA process, opening up the possibility of modifying the magnetism in the NiO/CoFe bilayers and offering an effective way to improve the performance of modern spintronic devices.

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Section: Introductionmentioning

confidence: 99%

“…The microstructural and magnetic properties of the CoFe=NiO bilayers were investigated with different annealing temperatures (T MFA = 523, 573, and 623 K). The CoFe thickness (20,30, and 40 nm) was tuned to study both the microstructural interface and volume effects on the magnetism of the CoFe=NiO bilayers.…”

Section: Introductionmentioning

confidence: 99%

Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co₉₀Fe₁₀bilayers

Zheng

Chiu

et al. 2017

Jpn. J. Appl. Phys.

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“…7) Among these methods, the ion-beam bombardment is an effective technique to modify the microstructural and compositional features of the FM=AF bilayers by altering crystallographic orientations, 8) changing grain sizes, 6) facilitating interlayer diffusion, 3,9) and so on. The altered microstructural and compositional properties can nontrivially influence the exchange bias and coercivity of the FM=AF bilayers, [2][3][4]8,10,11) revealing the critical role of the ion-beam bombardment in modifying the magnetism of the FM=AF bilayers.…”

Section: Introductionmentioning

confidence: 99%

Structural and magnetic characterization of Mn/NiFe bilayers with ion-beam-assisted deposition

Wu¹,

Zheng²,

Chiu³

et al. 2017

Jpn. J. Appl. Phys.

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The exchange bias effect in ferromagnetic (FM)/antiferromagnetic (AF) bilayer structures has been widely investigated because its underlying principle is critical for spintronic applications. In this work, the effect of Ar + beam bombardment on the microstructural and magnetic properties of the Mn/NiFe thin films was investigated. The in-situ Ar + bombardment nontrivially promoted the Mn/NiFe intermixing and facilitated the formation of the FeMn phase, accompanied by a remarkable reduction of Mn and NiFe layer thickness. The enhanced Mn/NiFe intermixing greatly disordered the interfacial spins, inhibiting the interfacial exchange coupling and giving rise to a significant decrease of the exchange bias field (H ex). The facilitated Mn/NiFe intermixing effect also dramatically degraded the magnetocrystalline anisotropy of the NiFe crystallites, leading to a notable suppression of the coercivity (H c). These results indicate that both the exchange bias and coercivity of the Mn/NiFe bilayers can be directly affected by the in-situ Ar + bombardment, offering an effective way to modify the magnetism of the exchange-bias systems.

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“…10 One of the experimental techniques already widely adopted for making high-quality MgO-based MTJs is to deposit an ultrathin Mg layer on top of the bottom ferromagnetic electrode layer prior to the deposition of MgO [11][12][13][14][15][16][17] or to insert a Mg interlayer at each electrode/barrier interface of the junction. 18 The advantages of inserting Mg interlayers include ͑1͒ the slightly but not fully oxidized Mg layer yields a low-resistance-area product of the junction while maintaining a high TMR ratio at the same time. 11 ͑2͒ It can also serve as a crystalline seed so that the texture of the subsequently deposited MgO͑001͒ barrier as well as the junction interface can be much improved.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of Fe/MgO based magnetic tunnel junctions with Mg interlayers

Wang

Zhang

et al. 2010

Phys. Rev. B

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magnetic tunnel junctions ͑MTJs͒ with Mg interlayers are studied by first-principles calculations. We find that the Mg interlayer is able to preserve the preferential transmission of the majority-spin states with ⌬ 1 symmetry, which dominates the spin-dependent electron transport in MTJs with MgO barrier. A monoatomic layer of Mg at the electrode/barrier interface does not decrease the tunneling magnetoresistance ͑TMR͒ ratio nearly as much as a similar layer of iron oxide. We also find that at a certain Mg thickness the TMR is strongly influenced by resonant tunneling in the minorityspin channel. These resonances are due to the coupling between the quantum-well states within the Mg interlayer to the interfacial resonance states on the Fe/Mg interface. The calculated results are used to explain experimental measurements of MTJs with Mg interlayers.

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Effect of Annealing and Barrier Thickness on MgO-Based Co/Pt and Co/Pd Multilayered Perpendicular Magnetic Tunnel Junctions

Cited by 21 publications

References 13 publications

Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co₉₀Fe₁₀bilayers

Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co₉₀Fe₁₀bilayers

Structural and magnetic characterization of Mn/NiFe bilayers with ion-beam-assisted deposition

First-principles study of Fe/MgO based magnetic tunnel junctions with Mg interlayers

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Effect of Annealing and Barrier Thickness on MgO-Based Co/Pt and Co/Pd Multilayered Perpendicular Magnetic Tunnel Junctions

Cited by 21 publications

References 13 publications

Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co90Fe10bilayers

Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co90Fe10bilayers

Structural and magnetic characterization of Mn/NiFe bilayers with ion-beam-assisted deposition

First-principles study of Fe/MgO based magnetic tunnel junctions with Mg interlayers

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Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co₉₀Fe₁₀bilayers

Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co₉₀Fe₁₀bilayers