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We present a detailed study of the spin-torque diode effect in CoFeB/MgO/CoFe/NiFe magnetic tunnel junctions. From the evolution of the resonance frequency with magnetic field at different angles, we clearly identify the free-layer mode and…

We propose an electrically driven spin injector into normal metals and semiconductors, which is based on a magnetic tunnel junction (MTJ) subjected to a microwave voltage. Efficient functioning of such an injector is provided by…

Mesoscale and Nanoscale Physics · Physics 2020-09-16 A. I. Nikitchenko , N. A. Pertsev

Future applications of spin-orbit torque will require new mechanisms to improve the efficiency for switching nanoscale magnetic tunnel junctions (MTJs), while also controlling the magnetic dynamics to achieve fast, nanosecond scale…

Mesoscale and Nanoscale Physics · Physics 2018-02-07 Shengjie Shi , Yongxi Ou , S. V. Aradhya , D. C. Ralph , R. A. Buhrman

Spin-transfer ferromagnetic resonance (ST-FMR) in symmetric magnetic tunnel junctions (MTJs) with a varied thickness of the MgO tunnel barrier (0.75 nm < $t_{MgO}$ < 1.05 nm) is studied using the spin-torque diode effect. The application of…

Using a first-principles noncollinear wave-function-matching method, we studied the spin-transfer torques (STTs) in CoFe/Mg-B-O/CoFe(001) magnetic tunnel junctions (MTJs), where three different types of B-doped MgO in the spacer are…

Mesoscale and Nanoscale Physics · Physics 2017-09-26 Ling Tang , Zhi-Jun Xu , Xian-Jun Zuo , Ze-Jin Yang , Qing-He Gao , Rong-Feng Linghu , Yun-Dong Guo

Modulation of a spin-torque oscillator (STO) signal based on a magnetic tunnel junction (MTJ) with perpendicularly magnetized free layer is investigated. Magnetic field inductive loop was created during MTJ fabrication process, which…

Applied Physics · Physics 2019-09-23 Witold Skowroński , Jakub Chęciński , Sławomir Ziętek , Kay Yakushiji , Shinji Yuasa

We perform an experimental study of DC current induced microwave emission in a magnetic tunnel junction (MTJ) consisting of three active magnetic layers. For this tri-layer structure, in addition to a conventional bilayer orthogonal MTJ…

Mesoscale and Nanoscale Physics · Physics 2020-07-22 R. N. S. Rajapakse , Z. M. Zeng , H. W. Jiang

We have developed and optimized two categories of spin transfer torque magnetic tunnel junctions (STT-MTJs) that exhibit a high tunnel magnetoresistance (TMR) ratio, low critical current, high outputpower in the micro watt range, and…

We present an experimental and theoretical study of the magnetic field dependence of the mode frequency of thermally excited spin waves in rectangular shaped nanopillars of lateral sizes 60x100, 75x150, and 105x190 nm2, patterned from…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 A. Helmer , S. Cornelissen , T. Devolder , J. -V. Kim , W. van Roy , L. Lagae , C. Chappert

Using a three-dimensional focused-ion beam lithography process we have fabricated nanopillar devices which show spin transfer torque switching at zero external magnetic fields. Under a small in-plane external bias field, a field-dependent…

Materials Science · Physics 2009-11-13 M. C. Wu , A. Aziz , D. Morecroft , M. G. Blamire , M. C. Hickey , M. Ali , G. Burnell , B. J. Hickey

Spin-momentum transfer between a spin-polarized current and a ferromagnetic layer can induce steady-state magnetization precession, and has recently been proposed as a working principle for ubiquitous radio-frequency devices for radar and…

A free electron description of spin-dependent tranport in magnetic tunnel junctions with non collinear magnetizations is presented. We investigate the origin of transverse spin density in tunnelling transport and the quantum interferences…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Aurélien Manchon , Natalya Ryzhanova , A. Vedyayev , Mairbek Chschiev , Bernard Dieny

A charge flow through a magnetic tunnel junction (MTJ) leads to the generation of a spin-polarized current which exerts a spin-transfer torque (STT) on the magnetization. When the density of applied direct current exceeds some critical…

Mesoscale and Nanoscale Physics · Physics 2019-07-10 A. I. Nikitchenko , N. A. Pertsev

We demonstrate a simple network-analyzer technique to make quantitative measurements of the bias dependence of spin torque in a magnetic tunnel junction. We apply a microwave current to exert an oscillating spin torque near the…

Mesoscale and Nanoscale Physics · Physics 2012-07-25 Lin Xue , Chen Wang , Yong-Tao Cui , J. A. Katine , R. A. Buhrman , D. C. Ralph

We demonstrate excitation of ferromagnetic resonance in CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) by the combined action of voltage-controlled magnetic anisotropy (VCMA) and spin transfer torque (ST). Our measurements reveal that…

Spin transfer torque oscillators (STOs) based on magnetic tunnel junction (MTJ) devices are emerging as a possible replacement for complementary metal-oxide semiconductors for radio-frequency (RF) signal generation. Advantages include low…

Emerging Technologies · Computer Science 2017-07-04 Supriyo Maji

We have measured spin transfer-induced dynamics in magnetic nanocontact devices having a perpendicularly magnetized Co/Ni free layer and an in-plane magnetized CoFe fixed layer. The frequencies and powers of the excitations agree well with…

Spin torque nano-oscillators are nanoscopic microwave frequency generators which excel due to their large frequency tuning range and agility for amplitude and frequency modulation. Due to their compactness, they are regarded as suitable…

The temperature dependence of a vortex-based nano-oscillator induced by spin transfer torque (STVO) in magnetic tunnel junctions (MTJ) is considered. We obtain emitted signals with large output power and good signal coherence. Due to the…

Materials Science · Physics 2015-06-03 P. Bortolotti , A. Dussaux , J. Grollier , V. Cros , A. Fukushima , H. Kubota , K. Yakushiji , S. Yuasa , K. Ando , A. Fert

We demonstrate spin torque induced auto-oscillation in MgO-based magnetic tunnel junctions. At the generation threshold, we observe a strong line narrowing down to 6 MHz at 300K and a dramatic increase in oscillator power, yielding…

Materials Science · Physics 2015-05-13 T. Devolder , S. Cornelissen , L. Bianchini , Joo-Von Kim , P. Crozat , C. Chappert , M. Op de Beeck , L. Lagae
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