Study on Exchange-Biased Perpendicular Magnetic Tunnel Junction Based on Pd/Co Multilayers

Lim, Dong-Won; Kim, Ki-Su; Kim, Sungdong; Jeung, Won Young; Lee, Seong-Rae

doi:10.1109/tmag.2009.2018590

Cited by 8 publications

(3 citation statements)

References 9 publications

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“…[1][2][3][4] Currently, perpendicular MTJs prepared using sputtering are actively being studied and have reached the tunnel magnetoresistance ͑TMR͒ ratios at room temperature ͑RT͒ of up to 64% with rare-earth transition metal alloys, [5][6][7] up to 120% with L1 0 -ordered ͑Co, Fe͒-Pt, 4,[8][9][10] and up to 15% with Co/͑Pd, Pt͒ multilayers. [11][12][13] For perpendicular MTJs, I c0 and E / k B T are in a trade-off relation. 1 In order to reduce I c0 , it is necessary to moderately reduce E / k B T. From this view point, multilayer electrodes have advantages; multilayer is relatively easy to control M s and H k by changing the number of the layer stack and the thicknesses.…”

Section: Mgo Barrier-perpendicular Magnetic Tunnel Junctions With Cofmentioning

confidence: 99%

MgO barrier-perpendicular magnetic tunnel junctions with CoFe/Pd multilayers and ferromagnetic insertion layers

Mizunuma¹,

Ikeda²,

Park³

et al. 2009

Applied Physics Letters

132

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The authors studied an effect of ferromagnetic (Co 20 Fe 60 B 20 or Fe) layer insertion on tunnel magnetoresistance (TMR) properties of MgO-barrier magnetic tunnel junctions (MTJs) with CoFe/Pd multilayer electrodes. TMR ratio in MTJs with CoFeB/MgO/Fe stack reached 67% at annealing temperature (T a ) of 200 o C and then decreased rapidly at T a over 250 o C. The degradation of the TMR ratio may be related to crystallization of CoFe(B) into fcc(111) or bcc(011) texture resulting from diffusion of B into Pd layers. MTJs which were in-situ annealed at 350 o C just after depositing bottom CoFe/Pd multilayer showed TMR ratio of 78% by post annealing at T a =200°C.

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Section: Mgo Barrier-perpendicular Magnetic Tunnel Junctions With Cofmentioning

confidence: 99%

MgO barrier-perpendicular magnetic tunnel junctions with CoFe/Pd multilayers and ferromagnetic insertion layers

Mizunuma¹,

Ikeda²,

Park³

et al. 2009

Applied Physics Letters

132

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“…Research on PMA began in the early 1980s, with Carcia et al achieving PMA in Co/Pd multilayers in 1985 [43]. Perpendicular anisotropy in Co/heavy metal (HM) multilayers is relatively easy to obtain, however, these multilayers tend to form fcc (111) texture, making it difficult to achieve compatibility with the bcc (100)-MgO discussed earlier, resulting in lower TMR [44,45]. Nishimura et al and Nakayama et al have also made perpendicular MTJs based on materials such as TbFeCo, but the incorporation of rare earth materials reduces the thermal stability of the film stack, inhibits the crystallization of MgO (001), and results in very low TMR (e.g.…”

Section: Mtjs With Perpendicular Magnetic Anisotropy (Pma)mentioning

confidence: 99%

Tunneling magnetoresistance materials and devices for neuromorphic computing

et al. 2023

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Artificial intelligence has become indispensable in modern life, but its energy consumption has become a significant concern due to its huge storage and computational demands. Artificial intelligence algorithms are mainly based on deep learning algorithms, relying on the backpropagation of convolutional neural networks or binary neural networks. While these algorithms aim to simulate the learning process of the human brain, their low bio-fidelity and the separation of storage and computing units lead to significant energy consumption. The human brain is a remarkable computing machine with extraordinary capabilities for recognizing and processing complex information while consuming very low power. Tunneling magnetoresistance (TMR)-based devices, namely magnetic tunnel junctions (MTJs), have great advantages in simulating the behavior of biological synapses and neurons. This is not only because MTJs can simulate biological behavior such as Spike-Timing Dependent Plasticity(STDP) and Leaky Integrate-Fire(LIF), but also because MTJs have intrinsic stochastic and oscillatory properties. These characteristics improve MTJs' bio-fidelity and reduce their power consumption. MTJs also possess advantages such as ultrafast dynamics and non-volatile properties, making them widely utilized in the field of neuromorphic computing in recent years. We conducted a comprehensive review of the development history and underlying principles of TMR, including a detailed introduction to the material and magnetic properties of MTJs and their temperature dependence. We also explored various writing methods of MTJs and their potential applications. Furthermore, we provided a thorough analysis of the characteristics and potential applications of different types of MTJs for neuromorphic computing. TMR-based devices have demonstrated promising potential for broad application in neuromorphic computing, particularly in the development of spiking neural networks. Their ability to perform on-chip learning with ultra-low power consumption makes them an exciting prospect for future advances in the era of the Internet of Things.

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“…Since PMA effect was investigated in (Pd/Co) N multilayer structure by Carcia et al in 1985s [13], many structures with induced PMA effect that mainly arise at the interface between 3d FM metals (compounds) and barriers have been found, such as Co/Pt(Pd) [14], CoFeB(Fe, CoFe)/MgO [15][16][17], Co 2 FeAl/MgO [18,19], Mn 3 Ga/SrTiO 3 [20] and FeN/BiFeO 3 [21] with PMA value of 0.9, 1.8, 2.01, 1.2 and 1.22 mJ m −2 , respectively. However, most of them either have a small PMA value or a low spin polarization that may result in a low tunnel magnetoresistance ratio (TMR) of the p-MTJs, which will greatly reduce the memory density of MRAM devices [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

The large perpendicular magnetic anisotropy induced at the Co₂FeAl/MgAl₂O₄ interface and tuned with the strain, voltage and charge doping by first principles study

Cheng¹,

Zhang²,

Yuan³

et al. 2021

Nanotechnology

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The heterostructures with high perpendicular magnetic anisotropy (PMA) have advantages for the application of the nonvolatile memories with long data retention time and small size. The interface structure and magnetic anisotropy energy (MAE) of Co2FeAl/MgAl2O4 heterostructures were studied by first principles calculations. The stable interface atomic arrangement is the Co or FeAl layer located above the equatorial oxygen coordinate in the distorted oxygen octahedrons. The Co–O interface can induce large effective PMA up to 4.54 mJ m−2, but this structure is a metastable structure. Meanwhile, the effective MAE decreases linearly as the thickness of the ferromagnetic layer increase. The effective MAE for the FeAl–O interface is only 1.3 mJ m−2, while the maximum thickness of Co2FeAl layer that maintains the PMA effect is about 1.717 nm. These values are very close to the experimental results. Through d-orbital-resolved MAE, we confirm that the interface PMA is mainly originated from the hybridization between and orbitals of interface 3d atoms. In addition, the compressive strain, negative electric field and hole doping can significantly enhance the effective PMA of FeAl–O interface. At the same time, Co–O interface will become the most stable structure by tuning the Mg/Al ratio in the spinel layers. The large effective PMA makes the Co2FeAl/MgAl2O4 junction a perfect candidate for the next-generation of non-volatile spintronic devices.

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Study on Exchange-Biased Perpendicular Magnetic Tunnel Junction Based on Pd/Co Multilayers

Cited by 8 publications

References 9 publications

MgO barrier-perpendicular magnetic tunnel junctions with CoFe/Pd multilayers and ferromagnetic insertion layers

MgO barrier-perpendicular magnetic tunnel junctions with CoFe/Pd multilayers and ferromagnetic insertion layers

Tunneling magnetoresistance materials and devices for neuromorphic computing

The large perpendicular magnetic anisotropy induced at the Co₂FeAl/MgAl₂O₄ interface and tuned with the strain, voltage and charge doping by first principles study

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Study on Exchange-Biased Perpendicular Magnetic Tunnel Junction Based on Pd/Co Multilayers

Cited by 8 publications

References 9 publications

MgO barrier-perpendicular magnetic tunnel junctions with CoFe/Pd multilayers and ferromagnetic insertion layers

MgO barrier-perpendicular magnetic tunnel junctions with CoFe/Pd multilayers and ferromagnetic insertion layers

Tunneling magnetoresistance materials and devices for neuromorphic computing

The large perpendicular magnetic anisotropy induced at the Co2FeAl/MgAl2O4 interface and tuned with the strain, voltage and charge doping by first principles study

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The large perpendicular magnetic anisotropy induced at the Co₂FeAl/MgAl₂O₄ interface and tuned with the strain, voltage and charge doping by first principles study