Inter-diffusion study in MgO tunneling magneto-resistive (TMR) system by XPS

Guo, Yu; Peng, Xilin

doi:10.1016/j.apsusc.2010.04.053

Cited by 11 publications

(6 citation statements)

References 18 publications

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“…9 and 10) at T a ¼ 425 C. Crystallization and texturing of CoFeB are important in the applications of spin valves because of their influence on TMR, 11 magnetic anisotropy, 12 and interface scattering. 4 To explain the crystallization process of CoFeB, different multilayer structures with CoFeB were examined by high resolution transmission electron microscopy (HRTEM) cross sectional images, 3,6,9,10,[13][14][15] reflective high-energy electron diffraction, 16 x-ray photoemission spectroscopy, [17][18][19][20] x-ray diffraction (XRD), 2,15,21-24 and x-ray reflectometry (XRR). [24][25][26] These XRD studies did not analyze CoFeB crystallization in P-SV compared to EB-SV.…”

Section: Introductionmentioning

confidence: 99%

X-ray diffraction analysis and Monte Carlo simulations of CoFeB-MgO based magnetic tunnel junctions

Kanak

Wiśniowski

Stobiecki

et al. 2013

Journal of Applied Physics

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Articles you may be interested inEffects of boron composition on tunneling magnetoresistance ratio and microstructure of CoFeB/MgO/CoFeB pseudo-spin-valve magnetic tunnel junctionsHere, we present the x-ray diffraction (XRD) analysis of a pseudo spin valve (P-SV): CoFeB/MgO/ CoFeB and an exchange bias spin valve (EB-SV): PtMn/CoFe/Ru/CoFeB/MgO/CoFeB magnetic tunnel junctions where the composition of CoFeB was (Co 52 Fe 48 ) 75 B 25 . In the P-SV, CoFeB layers crystallized into a highly bcc (001)-oriented CoFe texture while in the EB-SV, CoFeB crystallized into both (001)-oriented and (110)-oriented textures. Moreover, CoFeB crystallized better into the (001)-oriented texture when deposited on MgO than on a Ru layer. The P-SV and EB-SV devices with layer structures equivalent to the XRD samples, showed tunneling magnetoresistance of 240% and 180%, respectively. The Ru and Ta buffer layers annealed at 340 C mixed at the interface. The simulated crystalline structure and calculated h-2h profiles, using kinematical theory of x-ray scattering, correlated very well with the experimental profiles and confirmed Ta-Ru intermixing.

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Section: Introductionmentioning

confidence: 99%

X-ray diffraction analysis and Monte Carlo simulations of CoFeB-MgO based magnetic tunnel junctions

Kanak

Wiśniowski

Stobiecki

et al. 2013

Journal of Applied Physics

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“…Previous work using X-ray Photoelectron Spectroscopy (XPS) showed that annealing results in substantial Fe and Co diffusion into the MgO barrier in a simple Ta/CoFe/MgO/Ru stack. 49 Here, EFTEM revealed Co, Fe and O interdiffusion between the barrier and electrodes after annealing, which induces the apparent increase in barrier width. The fact that more Co diffused into the MgO than Fe is attributed to the much higher Co concentration of the FM layers in the as-deposited sample.…”

Section: Results and Discussion I: Effects Of Annealingmentioning

confidence: 75%

Effect of annealing and applied bias on barrier shape in CoFe/MgO/CoFe tunnel junctions

et al. 2011

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Energy-filtered transmission electron microscopy and electron holography were used to study changes in the MgO tunnel barrier of CoFe/MgO/CoFe magnetic tunnel junctions as a function of annealing and in-situ applied electrical bias. Annealing was found to increase the homogeneity and crystallinity of the MgO tunnel barrier. Cobalt, oxygen and trace amounts of iron diffused into the MgO upon annealing. Annealing also resulted in a reduction of the tunneling barrier height, and decreased the resistance of the annealed MTJ relative to that of the asgrown sample. In-situ off-axis electron holography was employed to image the barrier potential profile of an MTJ directly, with the specimen under electrical bias. Varying the bias voltage from −1.5 V to +1.5 V was found to change the asymmetry of the barrier potential and decrease the effective barrier width as a result of charge accumulation at the MgO-CoFe interface. Introduction Metal-oxide interfaces are the subject of extensive experimental and theoretical research for next generation nano-scale spintronic devices that exploit spin as a degree of freedom for charged electrons. 1 They play a key role in metal-oxide based science and engineering, with applications including magnetic tunnel junctions (MTJs) 2 and other heterogeneous structures such as resistance switching oxides 3 with uses or potentials uses in low-power non-volatile memories. In its simplest form, the MTJ is a trilayer structure consisting of two ferromagnetic (FM) electrode layers separated by an ultra-thin dielectric layer. The electrical resistance across the insulating tunnel barrier is dependent upon the relative orientation of the magnetizations of the two ferromagnetic electrodes. In most cases, the electrical resistance is lower when the magnetization of the two ferromagnetic layers is

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“…In terms of magnesium complex in Figure 2A, as leaching progresses, magnesium ferrite (centered at 29.58) [42] disappears as leaching duration reaches over 20 min. By comparing this with Figure 3A (XPS spectra of SL leached by NH 4 Cl at different time), in which significant drop of the intensity of XPS of Mg2p [43] are observed after 20 min, it indicates that the dissolution of magnesium ferrite is a quick process. The following reaction probably occurs during the first 20 min: …”

Section: Characterization Of Solid Residue After Leachingmentioning

confidence: 83%

NH₄Cl selective leaching of basic oxygen furnace slag: Optimization study using response surface methodology

Sun

Zhang

2016

Env Prog and Sustain Energy

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The basic oxygen furnace slag (SL) was selectively leached by NH4Cl. Response surface methodology and the central composite design (CCD) were employed in determining the optimal condition. The process parameters such as leaching duration, NH4Cl concentration, liquid solid ratio (LSR), and leaching temperature were chosen as independent variables in CCD. The quadratic model was developed for process optimization and statistical experimental designs. It is found that the leaching duration, NH4Cl concentration and liquid solid ratio are significant to the extraction of Ca2+ and Mg2+. The optimal conditions with setting maximum extraction of calcium and magnesium cations from SL are as following: 68 min (X1), 1.8 mol/L NH4Cl (X2), LSR 12 mL/g (X3), 53°C (X4), with the predicted Ca2+ and Mg2+ concentration reaching 13.3 and 3.2 g/L, respectively. The proposed simplified leaching mechanism indicates a two-stage leaching. The prone leachable MgFe2O4 and Ca2Fe2O5 are extracted in the fast stage, while the extraction of CaO occurs throughout slow stage. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1387–1394, 2016. © 2016 American Institute of Chemical Engineers Environ Pro

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Inter-diffusion study in MgO tunneling magneto-resistive (TMR) system by XPS

Cited by 11 publications

References 18 publications

X-ray diffraction analysis and Monte Carlo simulations of CoFeB-MgO based magnetic tunnel junctions

X-ray diffraction analysis and Monte Carlo simulations of CoFeB-MgO based magnetic tunnel junctions

Effect of annealing and applied bias on barrier shape in CoFe/MgO/CoFe tunnel junctions

NH₄Cl selective leaching of basic oxygen furnace slag: Optimization study using response surface methodology

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Inter-diffusion study in MgO tunneling magneto-resistive (TMR) system by XPS

Cited by 11 publications

References 18 publications

X-ray diffraction analysis and Monte Carlo simulations of CoFeB-MgO based magnetic tunnel junctions

X-ray diffraction analysis and Monte Carlo simulations of CoFeB-MgO based magnetic tunnel junctions

Effect of annealing and applied bias on barrier shape in CoFe/MgO/CoFe tunnel junctions

NH4Cl selective leaching of basic oxygen furnace slag: Optimization study using response surface methodology

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NH₄Cl selective leaching of basic oxygen furnace slag: Optimization study using response surface methodology