scholarly journals Spintronics - A Dive Into the Future

Author(s):  
Shahzeb Hussain ◽  
Shaayan Hussain

We already know that electrons have a charge along with a spin, but until recently, these two have been considered separately. The motion of electric charge is considered as the heart of electronic circuits, and the flow of electron spin plays a crucial role in spintronic circuits. Adding the spin degree of freedom provides new capabilities, new effects, and new functionalities. It all started with the discovery of the Giant Magnetoresistance (GMR) in 1988, which opened the road to an effective control of the motion of the electron charges by focusing on their spin through the orientation of magnetization. Today, spintronics has entered into almost every household as the read sensors for the hard drives present in every desktop and most laptops. Magnetic Random Access Memory (MRAM) and Spin Transfer Torque (STT) RAM are replacing Static RAM where ultra-dense memories are not required. Soon these spintronic memories will penetrate the cell phone market because they offer lower power and are non-volatile. The potential held by Spintronics is very promising for new advancements in science and technology in the 21st century. This paper discusses the evolution of spintronics from the initial research of spin-dependent transport in ferromagnetic materials to the discovery of the giant magnetoresistance and to the most recent advances. Today, this field of research is extending considerably, with very encouraging new technologies like the phenomena of spin transfer, molecular spintronics, nanoscale spintronics, and single-electron spintronics.

Author(s):  
T. Kimura

This chapter discusses the spin-transfer effect, which is described as the transfer of the spin angular momentum between the conduction electrons and the magnetization of the ferromagnet that occurs due to the conservation of the spin angular momentum. L. Berger, who introduced the concept in 1984, considered the exchange interaction between the conduction electron and the localized magnetic moment, and predicted that a magnetic domain wall can be moved by flowing the spin current. The spin-transfer effect was brought into the limelight by the progress in microfabrication techniques and the discovery of the giant magnetoresistance effect in magnetic multilayers. Berger, at the same time, separately studied the spin-transfer torque in a system similar to Slonczewski’s magnetic multilayered system and predicted spontaneous magnetization precession.


2012 ◽  
Vol 48 (11) ◽  
pp. 3025-3030 ◽  
Author(s):  
E. Chen ◽  
D. Apalkov ◽  
A. Driskill-Smith ◽  
A. Khvalkovskiy ◽  
D. Lottis ◽  
...  

2018 ◽  
Vol 185 ◽  
pp. 01015
Author(s):  
Niazbeck Useinov

The theoretical model of spin-dependent transport in magnetic tunnel junctions (MTJ) containing magnetic or non-magnetic nanoparticle is developed. The dependences of tunnel magnetoresistance (TMR) and in-plane component of spin transfer torque (STT) on the applied voltage for various sizes of nanoparticles of the order of the mean free path of the conduction electron are calculated. The calculation is performed in the approximation of the ballistic transport of conduction electrons through the insulating layers of the MTJ and the nanoparticles.


SPIN ◽  
2012 ◽  
Vol 02 (03) ◽  
pp. 1240001 ◽  
Author(s):  
ZIHUI WANG ◽  
YUCHEN ZHOU ◽  
JING ZHANG ◽  
YIMING HUAI

This paper reviews the recent progress made to realize reliable write operations in spin transfer torque magnetic random access memory. Theoretical description of write error rate (WER) based on macro-spin models are discussed with comparison to experimental data. Recent studies on the phenomena that can lead to abnormal WER behaviors which include back-hopping and low probability bifurcated switching are reviewed with emphasis on underlying mechanism. The studies on the WER in perpendicular magnetic tunnel junction (MTJ) are also reviewed. It is demonstrated that, for both in-plane and perpendicular MTJ, reliable and error-free write operations can be achieved with thorough understanding of the underlying physics and innovative design/process solutions.


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