scholarly journals Fabrication of soft-magnetic FeAlSi thin films with nm-order thickness for the free layer of magnetic tunnel junction based sensors

AIP Advances ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 015302
Author(s):  
Shoma Akamatsu ◽  
Mikihiko Oogane ◽  
Masakiyo Tsunoda ◽  
Yasuo Ando
Keyword(s):  
Thin Films ◽  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Free Layer ◽  
Soft Magnetic

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.

scholarly journals Voltage Controlled Domain Wall Motion based Neuron and Stochastic Magnetic Tunnel Junction Synapse for Neuromorphic Computing Applications

2021 ◽  
Author(s):  
Aijaz Lone ◽  
Selma Amara ◽  
Hossein Fariborzi
Keyword(s):  
Domain Wall ◽  
Tunnel Junction ◽  
Thermal Noise ◽  
Wall Motion ◽  
Magnetic Tunnel Junction ◽  
Domain Wall Motion ◽  
Spin Orbit ◽  
Free Layer ◽  
Digit Recognition ◽  
Transport Studies

The present work discusses the proposal of a spintronic neuromorphic system with spin orbit torque driven domain wall motion-based neuron and synapse. We propose a voltage-controlled magnetic anisotropy domain wall motion based magnetic tunnel junction neuron. We investigate how the electric field at the gate (pinning site), generated by the voltage signals from pre-neurons, modulates the domain wall motion, which reflects in the non-linear switching behaviour of neuron magnetization. For the implementation of synaptic weights, we propose 3-terminal MTJ with stochastic domain wall motion in the free layer. We incorporate intrinsic pinning effects by creating triangular notches on the sides of the free layer. The pinning of domain wall and intrinsic thermal noise of device lead to the stochastic behaviour of domain wall motion. The control of this stochasticity by the spin orbit torque is shown to realize the potentiation and depression of the synaptic weight. The micromagnetics and spin transport studies in synapse and neuron are carried out by developing a coupled micromagnetic Non-Equilibrium Green’s Function (<i>MuMag-NEGF</i>) model. The minimization of the writing current pulse width by leveraging the thermal noise and demagnetization energy is also presented. Finally, we discuss the implementation of digit recognition by the proposed system using a spike time dependent algorithm.

scholarly journals Structural Stability of Magnetic Tunnel Junction Based Molecular Spintronics Devices (MTJMSD)

2020 ◽  
Author(s):  
Joshua Dillard ◽  
Uzma Amir ◽  
Pawan Tyagi ◽  
Vincent Lamberti
Keyword(s):  
Thin Films ◽  
Structural Stability ◽  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Molecular Devices ◽  
Metal Electrodes ◽  
Molecular Spintronics ◽  
Ferromagnetic Electrodes

Abstract Harnessing the exotic properties of molecular level nanostructures to produce novel sensors, metamaterials, and futuristic computer devices can be technologically transformative. In addition, connecting the molecular nanostructures to ferromagnetic electrodes bring the unprecedented opportunity of making spin property based molecular devices. We have demonstrated that magnetic tunnel junction based molecular spintronics device (MTJMSD) approach to address numerous technological hurdles that have been inhibiting this field for decades (P. Tyagi, J. Mater. Chem., Vol. 21, 4733). MTJMSD approach is based on producing a capacitor like a testbed where two metal electrodes are separated by an ultrathin insulator and subsequently bridging the molecule nanostructure across the insulator to transform a capacitor into a molecular device. Our prior work showed that MTJMSDs produced extremely intriguing phenomenon such as room temperature current suppression by six orders, spin photovoltaic effect, and evolution of new forms of magnetic metamaterials arising due to the interaction of the magnetic a molecule with two ferromagnetic thin films. However, making robust and reproducible electrical connections with exotic molecules with ferromagnetic electrodes is full of challenges and requires attention to MTJMSD structural stability. This paper focuses on MTJMSD stability by describing the overall fabrication protocol and the associated potential threat to reliability. MTJMSD is based on microfabrication methods such as (a) photolithography for patterning the ferromagnetic electrodes, (b) sputtering of metallic thin films and insulator, and (c) at the end electrochemical process for bridging the molecules between two ferromagnetic films separated by ∼ 2nm insulating gap. For the successful MTJMSD fabrication, the selection of ferromagnetic metal electrodes and thickness was found to be a deterministic factor in designing the photolithography, thin film deposition strategy, and molecular bridging process. We mainly used isotropic NiFe soft magnetic material and anisotropic Cobalt (Co) with significant magnetic hardness. We found Co was susceptible to chemical etching when directly exposed to photoresist developer and aged molecular solution. However, NiFe was very stable against the chemicals we used in the MTJMSD fabrication. As compared to NiFe, the Co films with &gt; 10nm thickness were susceptible to mechanical stress-induced nanoscale deformities. However, cobalt was essential to produce (a) low leakage current before transforming the capacitor from the magnetic tunnel junction into molecular devices and (b) tailoring the magnetic properties of the ferromagnetic electrodes. This paper describes our overall MTJMSD fabrication scheme and process optimization to overcome various challenges to produce stable and reliable MTJMSDs. We also discuss the role of mechanical stresses arising during the sputtering of the ultrathin insulator and how to overcome that challenge by optimizing the insulator growth process. This paper will benefit researchers striving to make nanoscale spintronics devices for solving grand challenges in developing advanced sensors, magnetic metamaterials, and computer devices.

scholarly journals Isotropically coercive free layer integration in a magnetic tunnel junction for neuromorphic applications

2020 ◽  
Author(s):  
Marco Mansueto ◽  
Antoine Chavent ◽  
Ricardo Sousa ◽  
Liliana D. Buda-Prejbeanu ◽  
Ioan L. Prejbeanu ◽  
...  
Keyword(s):  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Free Layer

Compensation of orange-peel coupling effect in magnetic tunnel junction free layer via shape engineering for nanomagnet logic applications

2014 ◽  
Vol 115 (17) ◽  
pp. 17B902 ◽  
Author(s):  
Faisal A. Shah ◽  
Vijay K. Sankar ◽  
Peng Li ◽  
Gyorgy Csaba ◽  
Eugene Chen ◽  
...  
Keyword(s):  
Tunnel Junction ◽  
Coupling Effect ◽  
Magnetic Tunnel Junction ◽  
Orange Peel ◽  
Free Layer ◽  
Nanomagnet Logic

Effect of the stray field profile on the switching characteristics of the free layer in a perpendicular magnetic tunnel junction

2015 ◽  
Vol 117 (17) ◽  
pp. 17B721 ◽  
Author(s):  
Huang Jiancheng ◽  
Sim Cheow Hin ◽  
Vinayak Bharat Naik ◽  
Michael Tran ◽  
Lim Sze Ter ◽  
...  
Keyword(s):  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Stray Field ◽  
Field Profile ◽  
Free Layer ◽  
Switching Characteristics

Relation between exchange coupling and enhanced coercivity in the free layer of a patterned magnetic tunnel junction

2004 ◽  
Vol 96 (12) ◽  
pp. 7399-7402 ◽  
Author(s):  
CheolGi Kim ◽  
Chong-Oh Kim ◽  
Masakiyo Tsunoda ◽  
Migaku Takahashi ◽  
Tomasz Stobiecki
Keyword(s):  
Tunnel Junction ◽  
Exchange Coupling ◽  
Magnetic Tunnel Junction ◽  
Free Layer

Reduction of switching fields of submicrometer sized magnetic tunnel junction with NiFe-based synthetic ferrimagnetic free layer

2007 ◽  
Vol 101 (2) ◽  
pp. 023905 ◽  
Author(s):  
Young Min Lee ◽  
Yasuo Ando ◽  
Terunobu Miyazaki ◽  
Hitoshi Kubota
Keyword(s):  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Free Layer
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