Easy-cone state in spin-torque diode under combined action of magnetostatics and perpendicular anisotropy

2021 ◽  
Author(s):  
A. Buzdakov ◽  
Petr N. Skirdkov ◽  
Konstantin K Zvezdin
Keyword(s):  
Dynamic Properties ◽  
Perpendicular Magnetic Anisotropy ◽  
Magnetic Tunnel Junction ◽  
Spin Torque ◽  
Free Layer ◽  
Magnetostatic Interaction ◽  
Magnetostatic Field ◽  
Existence Region ◽  
Combined Action ◽  
Spatially Oriented

Abstract Spin-torque diodes (STDs) with interfacial perpendicular magnetic anisotropy (IPMA) in the free layer have outstanding microwave signal rectification performances. Large sensitivity values in such systems are usually associated with an easy cone (EC) magnetic state, when the magnetization in the free layer is tilted from the normal to the plane of the film. Here we theoretically investigate the phase diagram of the existence of an EC state in an infinite free layer of the magnetic tunnel junction (MTJ) considering both IPMA (first and second order) and magnetostatic interaction. We show that the increase of the magnetostatic field leads to extension of the EC existence region. Then we consider the effect of finite dimensions in case of two differently spatially oriented elliptic nanopillar MTJ on the obtained phase diagrams. And finally, we consider dynamic properties and rectification of two elliptic STD under microwave current injection. These results clarify magnetostatic interaction influence on IPMA based STD rectification and demonstrate possible approach to extend the parameters area of the EC STD highly effective rectification.

scholarly journals Spin Torque Oscillator for High Performance Magnetic Memory

2015 ◽  
Vol 20 (1) ◽  
pp. 77
Author(s):  
Rachid Sbiaa ◽  
Khaled Bouziane
Keyword(s):  
High Performance ◽  
Perpendicular Magnetic Anisotropy ◽  
Magnetic Tunnel Junction ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Magnetic Memory ◽  
Spin Torque ◽  
Free Layer ◽  
Switching Current ◽  
Thermal Stability Of

A study on spin transfer torque switching in a magnetic tunnel junction with perpendicular magnetic anisotropy is presented. The switching current can be strongly reduced under a spin torque oscillator (STO), and its use in addition to the conventional transport in magnetic tunnel junctions (MTJ) should be considered. The reduction of the switching current from the parallel state to the antiparallel state is greater than in  the opposite direction, thus minimizing the asymmetry of the resistance versus current in the hysteresis loop. This reduction of both switching current and asymmetry under a spin torque oscillator occurs only during the writing process and does not affect the thermal stability of the free layer.

scholarly journals Magnetization Dynamics in a Perpendicular Anisotropy Free Layer under a Spin Torque Effect with Crossed Polarization

2020 ◽  
Vol 25 (1) ◽  
pp. 54
Author(s):  
Nafeesa Rahman ◽  
Rachid Sbiaa
Keyword(s):  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Film Plane ◽  
Spin Torque ◽  
Spin Angular Momentum ◽  
Perpendicular Anisotropy ◽  
Free Layer ◽  
Magnetization Dynamics ◽  
Magnetization Direction ◽  
Spin Polarized

The transfer of spin angular momentum from a spin polarized current provides an efficient way of reversing the magnetization direction of the free layer of the magnetic tunnel junction (MTJ), and while faster reversal will reduce the switching energy, this in turn will lead to low power consumption. In this work, we propose a design where a spin torque oscillator (STO) is integrated with a conventional magnetic tunnel junction (MTJ) which will assist in the ultrafast reversal of the magnetization of the free layer of the MTJ. The structure formed (MTJ stacked with STO), will have the free layer of the MTJ sandwiched between two spin polarizer layers, one with a fixed magnetization direction perpendicular to film plane (main static polarizer) and the other with an oscillatory magnetization (dynamic polarizer). The static polarizer is the fixed layer of the MTJ itself and the dynamic polarizer is the free layer of the STO.

Spin-Torque Oscillator Based on Magnetic Tunnel Junction with a Perpendicularly Magnetized Free Layer and In-Plane Magnetized Polarizer

2013 ◽  
Vol 6 (10) ◽  
pp. 103003 ◽  
Author(s):  
Hitoshi Kubota ◽  
Kay Yakushiji ◽  
Akio Fukushima ◽  
Shingo Tamaru ◽  
Makoto Konoto ◽  
...  
Keyword(s):  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Spin Torque ◽  
Free Layer

Spin torque in uniform magnetization

2017 ◽  
Author(s):  
Y. Suzuki
Keyword(s):  
Barrier Layer ◽  
Tunnel Junction ◽  
Spin Current ◽  
Magnetic Tunnel Junction ◽  
Spin Torque ◽  
Free Layer ◽  
Nonmagnetic Metal ◽  
Uniform Magnetization ◽  
Spin Polarized ◽  
Ferromagnetic Layers

This chapter discusses the effects of a spin current injected into a uniformly magnetized ferromagnetic cell. The junction consists of two ferromagnetic layers separated by a nonmagnetic metal interlayer or insulating barrier layer. With a nonmagnetic metal interlayer, the junction is called a giant magnetoresistive nanopillar, and with an insulating barrier layer a magnetic-tunnel junction. When charge current is passed through this device, the electrons are first spin polarized by the fixed layer and spin-polarized current is then injected into the free layer through the nonmagnetic interlayer. This spin current interacts with the spins in the host material by an exchange interaction and exerts a torque. If the exerted torque is large enough, magnetization in the free layer is reversed or continuous precession is excited.

Spin torque diode effect of the magnetic tunnel junction with MnGa free layer

2018 ◽  
Vol 112 (26) ◽  
pp. 262408 ◽  
Author(s):  
Sumito Tsunegi ◽  
Kotaro Mizunuma ◽  
Kazuya Suzuki ◽  
Hiroshi Imamura ◽  
Shingo Tamaru ◽  
...  
Keyword(s):  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Spin Torque ◽  
Free Layer

scholarly journals Current-induced spin–orbit torques

2011 ◽  
Vol 369 (1948) ◽  
pp. 3175-3197 ◽  
Author(s):  
Pietro Gambardella ◽  
Ioan Mihai Miron
Keyword(s):  
Angular Momentum ◽  
Exchange Coupling ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Spin Torque ◽  
Inversion Symmetry ◽  
Spin Orbit ◽  
Great Flexibility ◽  
Combined Action ◽  
Proper Material

The ability to reverse the magnetization of nanomagnets by current injection has attracted increased attention ever since the spin-transfer torque mechanism was predicted in 1996. In this paper, we review the basic theoretical and experimental arguments supporting a novel current-induced spin torque mechanism taking place in ferromagnetic (FM) materials. This effect, hereafter named spin–orbit (SO) torque, is produced by the flow of an electric current in a crystalline structure lacking inversion symmetry, which transfers orbital angular momentum from the lattice to the spin system owing to the combined action of SO and exchange coupling. SO torques are found to be prominent in both FM metal and semiconducting systems, allowing for great flexibility in adjusting their orientation and magnitude by proper material engineering. Further directions of research in this field are briefly outlined.

Sign in / Sign up

Export Citation Format

Share Document