Analysis and Compact Modeling of Magnetic Tunnel Junctions Utilizing Voltage-Controlled Magnetic Anisotropy

Lee, Hochul; Lee, Albert; Wang, Shaodi; Ebrahimi, Farbod; Gupta, Puneet; Amiri, Pedram Khalili; Wang, Kang L.

doi:10.1109/tmag.2017.2788010

Cited by 32 publications

(20 citation statements)

References 36 publications

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“…This paper reviews recent progress in the research of the VCMA effect and the challenges that are faced in developing new types of MRAM controlled by voltage, called voltage-torque MRAM (also called Magnetoelectric (ME)-RAM) [34,35,36,37,38,39]. Section 2 presents an overview of the early experimental observations of the VCMA effect in all-solid state devices and the concept of voltage-induced dynamic switching, with a discussion of the technical challenges.…”

Section: Introductionmentioning

confidence: 99%

Recent Progress in the Voltage-Controlled Magnetic Anisotropy Effect and the Challenges Faced in Developing Voltage-Torque MRAM

et al. 2019

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The electron spin degree of freedom can provide the functionality of “nonvolatility” in electronic devices. For example, magnetoresistive random access memory (MRAM) is expected as an ideal nonvolatile working memory, with high speed response, high write endurance, and good compatibility with complementary metal-oxide-semiconductor (CMOS) technologies. However, a challenging technical issue is to reduce the operating power. With the present technology, an electrical current is required to control the direction and dynamics of the spin. This consumes high energy when compared with electric-field controlled devices, such as those that are used in the semiconductor industry. A novel approach to overcome this problem is to use the voltage-controlled magnetic anisotropy (VCMA) effect, which draws attention to the development of a new type of MRAM that is controlled by voltage (voltage-torque MRAM). This paper reviews recent progress in experimental demonstrations of the VCMA effect. First, we present an overview of the early experimental observations of the VCMA effect in all-solid state devices, and follow this with an introduction of the concept of the voltage-induced dynamic switching technique. Subsequently, we describe recent progress in understanding of physical origin of the VCMA effect. Finally, new materials research to realize a highly-efficient VCMA effect and the verification of reliable voltage-induced dynamic switching with a low write error rate are introduced, followed by a discussion of the technical challenges that will be encountered in the future development of voltage-torque MRAM.

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Section: Introductionmentioning

confidence: 99%

Recent Progress in the Voltage-Controlled Magnetic Anisotropy Effect and the Challenges Faced in Developing Voltage-Torque MRAM

et al. 2019

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“…where t ox andφ are respectively the thickness and potential barrier height of the tunnel barrier layer, F is the fitting factor calculated from the resistance-area product (R•A), A MTJ is the section area of the MTJ, e is the elementary charge, m is the electron mass andh is the reduced planck constant. The tunnel magnetoresistance ratio (TMR) is a parameter that describes the resistance difference of the MTJ between the AP and P state, which can be expressed by [27] TMR =…”

Section: Tunnel Magnetoresistance Module Of the Vgsot-mtjmentioning

confidence: 99%

“…The PMA may stem from a preference of the spins to align in the perpendicular direction due to the interfacial or magnetocrystalline effect and can be described as follows [27]:…”

Section: ) Perpendicular Magnetic Anisotropy Fieldmentioning

confidence: 99%

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Compact Modeling and Analysis of Voltage-Gated Spin-Orbit Torque Magnetic Tunnel Junction

Zhang

Wang

et al. 2020

IEEE Access

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Recently, experimental results have demonstrated that perpendicular magnetic tunnel junction (p-MTJ) with the antiferromagnetic(AFM)/ferromagnetic (FM)/oxide structure can achieve field-free spinorbit torque (SOT) switching since the AFM metal strip can not only generate the SOT, but also provide an exchange bias (H EX), making it suitable for practical applications. However, owing to that the H EX is weak, such field-free SOT switching is incomplete, thus resulting in severe switching reliability. In addition, a large SOT switching current (I SOT) is also required, leading to high switching energy dissipation. In this paper, to address these issues, the voltage-controlled magnetic anisotropy (VCMA) is introduced to assist the SOT switching, and such novel switching method is referred as voltage-gated SOT (VGSOT). First, we develop a physics-based compact model for the three-terminal VGSOT-MTJ device, which includes three modules, i.e., the electrical module, the tunnel magnetoresistance module and the dynamic switching module. Then, the impact of the VCMA effect on the field-free SOT switching is investigated by solving a modified Landau-Lifshitz-Gilbert (LLG) equation with consideration of the VCMA, SOT and H EX. Simulation results show that thanks to the introduction of the VCMA effect, the critical I SOT can be reduced greatly, and the incomplete field-free SOT switching can be completed. With further analysis, we obtain a special switching condition, under which complete SOT field-free switching can be achieved with a shortest path and ultra-low power. Moreover, a novel write pulse scheme is proposed to achieve high speed and reliability. INDEX TERMS p-MTJ, antiferromagnetic, field-free SOT switching, exchange bias, VCMA, voltage-gated SOT, compact model, ultra-low power, high speed and reliability.

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“…The PMA is then modulated through the electric field induced by the MTJ current. This change in PMA, called voltage controlled magnetic anisotropy (VCMA) can be explained in terms of the Rashba spin-orbit coupling and change in occupancy of atomic orbitals in thin (<2 nm) ferromagnetic layers [31]- [33]. Thus, when developing the three-terminal MTJ-SHNO model, these phenomena need to be included for accurate modeling.…”

Section: A Basic Operation Of Three-terminal Mtj-shnos With Vcmamentioning

confidence: 99%

Compact Macrospin-Based Model of Three-Terminal Spin-Hall Nano Oscillators

et al. 2019

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Analysis and Compact Modeling of Magnetic Tunnel Junctions Utilizing Voltage-Controlled Magnetic Anisotropy

Cited by 32 publications

References 36 publications

Recent Progress in the Voltage-Controlled Magnetic Anisotropy Effect and the Challenges Faced in Developing Voltage-Torque MRAM

Recent Progress in the Voltage-Controlled Magnetic Anisotropy Effect and the Challenges Faced in Developing Voltage-Torque MRAM

Compact Modeling and Analysis of Voltage-Gated Spin-Orbit Torque Magnetic Tunnel Junction

Compact Macrospin-Based Model of Three-Terminal Spin-Hall Nano Oscillators

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