RECENT DEVELOPMENTS IN SPINTRONIC DEVICES

Spintronics is one of the emerging fields for the next-generation nanoelectronic devices that are used to reduce their power consumption, and increase their memory and processing capabilities. Such devices used for the spin degree of freedom of electrons and/or holes, which can also interact with their orbital moments [1]. However, for spintronic devices to meet the ever-increasing demands of the industry, innovation in terms of materials, processes, and circuits are required.

Figure 1. Schematic diagram for major methods to generate a spin-polarised current [2].

Spin-polarised electrons can be generated in non-magnetic (NM) materials using the following methods [2]: spin injection from a ferromagnetic (FM), a magnetic field, an electric field, an electromagnetic wave introduction, a thermal gradient, Zeeman splitting, spin motive force, and mechanical rotation (see Figure 1). One of the most common methods is spin injection from a FM material, e.g., conventional FM metals (Fe, Co, Ni and Gd), half-metallic ferromagnets (HMF) and dilute magnetic semiconductors (DMS), are attached to a NM metal or semiconductors (SC) through an ohmic contact or a tunnel barrier. A stray field at the edge of a FM can also be used to induce a population difference in spin-polarized electrons in a NM material.

B. Dieny et al., have been developed that spintronics can apply in four key areas: magnetic memories, magnetic sensors, radio-frequency and microwave devices, logic and non-Boolean devices [3].

On the other hand of spintronic devices, exploit the spin of electrons to generate and control charge currents, and to interconvert electrical and magnetic signals. By combining processing, storage, sensing, and logic within a single integrated platform, spintronics could complement and, in some cases, outperform semiconductor-based electronics, offering advantages in terms of scaling, power consumption, and data processing speed.

Figure 2. Typical magnetic length scales and the development of magnetic storage devices [2].

In this field, already established many large-scale commercial applications such as Giant magnetoresistance (GMR)-based spin valves and magnetic tunnel junctions (MTJs) have been used as magnetic field sensors in tape and hard disk drive read heads, as position or proximity sensors in cars, automated industrial tools, and biomedical devices. The typical length scales of magnetic devices and systems are listed in Figure 2.

Therefore researchers from this field need to concentrate on these for future developments:

The current and future capabilities of spintronics to the broader electronics community.
To encourage the spintronics community to focus on, and think about it for applications.
The ultimate goal and being a help to translate basic research into industrial technologies and economic gains.
Spintronic devices were optimized for low-temperature operation for quantum engineering or large scale computers.

In particular, the following items should be considered for further improvements or new directions in spintronic device applications from Ref. [1]:

Low power read-out using spin–orbit phenomena rather than tunnel magneto resistance.
Innovative circuits architecture taking full advantage of spintronic phenomena, materials and devices (e.g., in memory computing, normally-off/instant-on architecture).
Unconventional computing using spintronic devices (e.g., stochasticcomputing).
Innovative magnetic field sensors with increased sensitivity, reduced temperature dependence, or broader field dynamics for all kinds of applications from position encoders to medical diagnosis or HDD read-heads.
Coupling of photonics and nanomagnetism/spintronics to the development of optical interconnects in electronics and all optical writing in storage technology.
3D spintronic embodiments for high-density memory and storage devices.
Energy harvesting from thermal gradients via spincaloritronics or electromagnetic radiations using spin-diodes.
Development of artificial neurons and synpases for artificial intelligence based on spintronic devices.
Spintronic devices optimized for low-temperature operation for quantum engineering or large scale computers.

References

A. Hirohata et al., J. Mag. Magn. Mat. 509, 166711 (2020).
A. Hirohata, K. Takanashi, J. Phys. D: Appl. Phys. 47, 193001 (2014).
B. Dieny et al., Nature Electronics, 3, 446 (2020).

Blog Written By

Dr. A. S. Ganeshraja

Assistant Professor

National College, Tiruchirappalli

Tamil Nadu, India

Editors

Dr. K. Rajkumar

Dr. S. Chandrasekar

Reviewers

Dr. Y. Sasikumar

Dr. S. Thirumurugan

Comments

Designing of Corrosion Resistant Alloys via Percolation Theory

Canada and USA Scientists have reported on designing of corrosion-resistant alloys via percolation theory and published in Nature Materials on 01 February 2021. Nickel–chromium, Iron–chromium binary alloys can serve as the prototypical corrosion-resistant metals owing to its presence of a nanometre-thick protective passive oxide film. The main key criterion for good passive behavior is the passive film should be compromised via a scratch or abrasive wear that can be reformed with a little metal dissolution. This could be a principal reason for the stainless steels and other chromium containing alloys that are used for critical applications which ranges from nuclear reactor components to biomedical implants. A long-standing unanswered question in corrosion science is the unravelling of the compositional dependence of the electrochemical behavior of the alloys [ 1, 2 ]. The discovery of the family of these alloys were increased its rate with the advent of artificial intelligence, da...

Innovations of Integrated Artificial Intelligence

Artificial intelligence (AI) is the study of methods to imitate intelligent human behavior. AI is widely heralded as an ongoing “revolution” transforming science and society altogether [ 1 , 2 ]. While approaches to AI such as machine learning, deep learning and artificial neural networks are reshaping data processing and analysis [ 3 ], healthcare, transportation and the production chain [ 4 ]. Figure 1. Integrated concept of artificial intelligence. AI Ethics Guidelines National and international organizations (European Commission, Organisation for Economic Co-operation and Development (OECD), UK House of Lords, Singapore Commission) have responded to these concerns by developing ad hoc expert committees on AI, often mandated to draft policy documents in various countries. In 2018 alone, companies such as Google and SAP publicly released AI guidelines and principles. The advisory council on the ethical use of AI scientific team have announced that results reveal a global co...

Electro-Organic Synthesis: Next Emerging Technique

Industrial developments, excessive energy consumption, sustainable technologies, environmental cleaning processes are major topics of political and social discourse. Current innovations are rated not only focusing on their benefit and utility but also concerning their eco-friendly approaches. The development of green technological processes is becoming more important and requires harmless energy sources. Particularly over the past decade, the severe limitations of fossil resources intensify the movement towards sustainable synthesis techniques with a strict cutback in the ecological footprint [ 1 ]. Electro-organic synthesis belongs to the synthetic organic chemistry discipline that facilities the direct use of electricity to generate valuable compounds. Hence, it is possible to transfer green aspects of sustainable energy sources to the whole production process [ 2 ]. Since the Kolbe’s discoveries of using electricity as a reagent for organic transformations over 170 years ago, ...

Bifunctional Water Splitting Catalysts: Large Current Density

Fuel cell technology is one of the most emerging fields with ecofriendly and everlasting energy source way of producing energy for the urgent requirements. Further it needs to be improved to make it cheap and more environmental friendly. Among all fuel cells, the hydrogen (H 2 ) and oxygen (O 2 ) fuel cell is the one with zero carbon emission, more ecofriendly, high potential and the byproduct is just only the water. However, supplying the fuels in the purest form (at least the H 2 ) is very essential to ensure higher life cycles and less decay in cell efficiency. Nowadays, commercially available large scale H 2 production is mainly dependent on steam reforming of fossil fuels which can also generates CO 2 along with H 2 and the source that is going to be depleted, and this byproduct is not environmental friendly. Therefore, an emerging alternate technology is needed; in this case the electrolysis of water has given a greater attention than the steam reforming. Recently man...

Single-Atom Catalysis in Chemistry World

The recent interest on the heterogeneous single-atom catalysts (SACs) were composed of atomically dispersed active metal cen ters in catalyst research field, because of the increased atom utilization and unique catalytic properties of such materials, which differ greatly from those of conventional nano or subnano counter parts. In this case, the fabrication of SACs are challenging, especially in the case of noble metal based catalysts and many researches are ongoing in this field for the development of improved catalysts. Many chall enges have faced for the hybridization of controlling of single atoms in suitable host materials, but it has also equally opened with unique opportunities for catalyst design. SACs with atomically dispersed active metal centers on supports represent an intermediary between heterogeneous and homogeneous catalysis. Therefore, understanding the homogeneous catalysis prototype creates a great opportunity for designing SACs and developing related applications....

Application of the MOFs-Drug Delivery System

Metal Organic Frameworks (MOFs) are constructed by metal ions/clusters and multidentate organic linkers via coordination bonds (reticular synthesis) have significantly enriched the domain of porous materials [ 1 , 2 ]. Based on the flexibility of the constituents, geometry, size and functionality, MOFs with a crystalline nature possess extremely high surface areas (typically ranging from 1000 to 10,000 m 2 g -1 ) and tunable pore sizes/characteristics. These aspects endow MOFs with fantastic functionalities/properties for a variety of applications such as gas adsorption, separation, catalysis, sensors, drug delivery, proton conduction etc [ 2 ]. In the de novo synthesis of MOFs, ligands with relatively high pKa (e.g. azoles) easily produce robust frameworks with low-valent metal ions, while linkers with relatively low pKa (e.g. carboxylic acids) tend to bind with high-valent metal ions to give stable structures. In general, dense and rigid frameworks are constructed by rigid and h...

Novel Approach of Plastic Waste to Flash Graphene

Prof. Algozeeb and his research collaboration team have investigated an novel approach of upcycling plastic waste (PW) products to flash graphene (FG). This method relies on Flash Joule Heating (FJH) to convert PW into FG. A sequential direct current (DC) and alternating current (AC) flash is used in order to make a high-quality graphene. In this FJH process, they established without catalyst and works for PW mixtures that can make the process suitable for handling landfill PW. In 21 st century, PW pollution is considerable one among the various environmental issues. A very large fraction of PW ends up in the ocean, which leads to the formation of micro- and nanoplastics that threaten marine life, micro-organisms, useful bacteria, and humans. From the intense carbon footprint process, most of these synthesized plastics are used only once before dumping into landfills or water ways that terminate in the oceans. Hence, upcycling PW to higher value materials and chemicals is econ...

Postdocs Crisis: The "Last Generation" of Scientists

Postdoctoral Researchers play a vital role in the research productivity of several countries and serving as leaders, mentors, guides, teachers, and scientists. These researchers have developed their own skills and preparing themself for their scientific research careers with various research groups worldwide. Even performing in a short term, they need to spend additional years in some special cases for succession in their research careers. Senior research investigators or leaders who have promised to their younger colleagues or students for a long term contract in the academics should find a new pathway to make it possible to stay and plan for their long-term career. Also, these investigators should be more flexible, patience, and supportive for everyone in their research groups. But the main key point which they should focus on that was the researchers who want to pursue fulfilling careers in science elsewhere need to be supported in all means, whatever matters, whoever may be, the ta...

Hot Hole-Deriven Water Splitting via LSPR Metal Nanostructures

The localized surface plasmon resonance (LSPR) in metal nanostructures is one of the most efficient materials for the futuristic energy, environmental science and industry. The new era is the ability to significantly drive and promote photocatalytic reactions and photodetection which acts as an interfacial energy transfer to adsorbate molecules and semiconductors. The combination of plasmonic noble metallic nanostructures with semiconductors for plasmon-enhanced visible light-driven water splitting (WS) has attracted considerable attention. WS is one of the most capable way to save solar energy into other useful energy applications. In WS, solar energy is converted to chemical energy mainly in the form of hydrogen and oxygen. Some of the review reports indicate that the highest reported quantum efficiency for overall WS achieved is 57% with NiO/NaTaO 3 :La photocatalyst under the excitation wavelength of 270 nm [1]. Its large scale commercial applications a...

Search This Blog