Impact of Spin-Transfer Torque on the Write-Error Rate of a Voltage-Torque-Based Magnetoresistive Random-Access Memory

Imamura, Hiroshi; Matsumoto, Rie

doi:10.1103/physrevapplied.11.064019

Cited by 6 publications

(4 citation statements)

References 50 publications

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“…The MgO layer thickness is adjusted so that the resistance–area product becomes approximately 1000 Ω μm 2 . This large resistance–area product effectively suppresses the effects of spin-transfer torque . The magnetization direction of the (Co 10 Fe 90 ) 80 B 20 layer is fixed using a [Co/Pt]-based perpendicularly magnetized synthetic antiferromagnetic layer, whereas the (Co 48 Fe 52 ) 80 B 20 has a free magnetization whose perpendicular magnetic anisotropy (PMA) can be modulated by the external electric fields.…”

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confidence: 99%

“…This large resistance−area product effectively suppresses the effects of spin-transfer torque. 38 The magnetization direction of the (Co 10 Fe 90 ) 80 B 20 layer is fixed using a [Co/Pt]-based perpendicularly magnetized synthetic antiferromagnetic layer, whereas the (Co 48 Fe 52 ) 80 B 20 has a free magnetization whose perpendicular magnetic anisotropy (PMA) can be modulated by the external electric fields. The whole stack is prepared by using an ultrahigh vacuum magnetron sputtering system at room temperature.…”

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Voltage-Driven Magnetization Switching Controlled by Microwave Electric Field Pumping

et al. 2020

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We study the dynamic switching properties of a nanomagnet under microwave electric field pumping. The periodic modulation of an anisotropy field induced by microwave electric field pumping efficiently excites the uniform magnetization oscillation, allowing for precise control of magnetization switching. Accurate shaping of the pumping voltage waveform also enables us to investigate the transient reaction of magnetization to the relative phase difference of the pumping signal. We demonstrate both experimentally and theoretically the existence of a dead angle in which the uniform oscillation of magnetization is inhibited even though the microwave frequency itself satisfies the conditions of parametric excitation. Our results provide an energy-efficient way of manipulating ultrafast magnetization dynamics in nanomagnetic devices.

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Voltage-Driven Magnetization Switching Controlled by Microwave Electric Field Pumping

et al. 2020

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“…The mechanism of VCMA in an MgO-based MTJ is considered to be the combination of the selective electron or hole doping into the d-electron orbitals and the induction of a magnetic dipole moment, which affect the electron spin through spin-orbit interaction [18][19][20]27]. The MRAM which uses the VCMA effect to switch magnetization is called the voltage controlled MRAM (VC-MRAM) [28][29][30][31][32][33][34][35][36][37][38][39][40]. The writing procedure of a conventional VC-MRAM is as follows.…”

Section: Introductionmentioning

confidence: 99%

Low power switching of magnetization using enhanced magnetic anisotropy with short-voltage-pulse application

Matsumoto,

Imamura

2020

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A low power magnetization switching scheme based on the voltage control of magnetic anisotropy (VCMA) is proposed. In contrast to the conventional switching scheme using VCMA, where the magnetic anisotropy is eliminated during the voltage pulse, the magnetic anisotropy is enhanced to induce precession around the axis close to the easy axis. After turning off the voltage proximately at a half of precession period, the magnetization relaxes to the opposite equilibrium direction. We perform numerical simulations and show that the pulse duration of the proposed switching scheme is as short as a few tens of pico seconds. Such a short pulse duration is beneficial for low power consumption because of the reduction of energy loss by Joule heating.

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“…The discovery of voltage controlled magnetic anisotropy (VCMA) effect [7][8][9][10][11][12][13] provides a more energy-efficient writing scheme of MRAM. In the VCMA-based switching [14][15][16][17][18][19][20][21][22][23][24], application of the voltage to the MRAM cell eliminates the MA of the free layer (FL) and induces the precession of magnetization around the external magnetic field. The switching completes if the voltage is turned off at a half period of precession.…”

Section: Introductionmentioning

confidence: 99%

Large angle precession of magnetization maintained by a microwave voltage

Imamura,

Matsumoto

2020

Preprint

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Effects of a microwave voltage on magnetization precession are analyzed based on a macrospin model. The microwave voltage induces the oscillating anisotropy field through the voltage controlled magnetic anisotropy (VCMA) effect, and then stimulates the magnetization. The large angle precession is maintained if the magnetization synchronizes with the microwave voltage. The effective equations of motion of the magnetization with an oscillating anisotropy field are derived, and the mechanism of the synchronization is clarified by analyzing the derived equations of motion. The conditions of the angular frequency detuning and the amplitude of the oscillating anisotropy field for synchronization are obtained. The results are useful for development of the VCMA-based energyefficient spintronics devices using magnetization precession such as a VCMA-based magnetoresistive random access memory and a nano-scale microwave magnetic field generator.

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Impact of Spin-Transfer Torque on the Write-Error Rate of a Voltage-Torque-Based Magnetoresistive Random-Access Memory

Abstract: J p = 0 J p = 10 9 A/m 2 J p = 10 10 A/m 2 J p = 10 11 A/m 2 J p = 10 12 A/m 2 J p = 0 J p = 10 9 A/m 2 J p = 10 10 A/m 2 J p = 10 11 A/m 2 J p = 10 12 A/m 2

Cited by 6 publications

References 50 publications

Voltage-Driven Magnetization Switching Controlled by Microwave Electric Field Pumping

Voltage-Driven Magnetization Switching Controlled by Microwave Electric Field Pumping

Low power switching of magnetization using enhanced magnetic anisotropy with short-voltage-pulse application

Large angle precession of magnetization maintained by a microwave voltage

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