Information Storage Technology Research Articles

Challenges for exploiting nanomagnet properties on surfaces.

Molecular complexes with single-molecule magnet (SMM) or qubit properties, commonly called molecular nanomagnets, are great candidates for information storage or quantum information processing technologies. However, the implementation of molecular nanomagnets in devices for the above-mentioned applications requires controlled surface deposition and addressing the nanomagnets' properties on the surface. This Perspectives paper gives a brief overview of molecular properties on a surface relevant for magnetic molecules and how they are affected when the molecules interact with a surface; then, we focus on systems of increasing complexity, where the relevant SMMs and qubit properties have been observed for the molecules deposited on surfaces; finally, future perspectives, including possible ways of overcoming the problems encountered so far are discussed.

Understanding Antiferromagnetic Coupling in Lead-Free Halide Double Perovskite Semiconductors.

Solution-processable semiconductors with antiferromagnetic (AFM) order are attractive for future spintronics and information storage technology. Halide perovskites containing magnetic ions have emerged as multifunctional materials, demonstrating a cross-link between structural, optical, electrical, and magnetic properties. However, stable optoelectronic halide perovskites that are antiferromagnetic remain sparse, and the critical design rules to optimize magnetic coupling still must be developed. Here, we combine the complementary magnetometry and electron-spin-resonance experiments, together with first-principles calculations to study the antiferromagnetic coupling in stable Cs2(Ag:Na)FeCl6 bulk semiconductor alloys grown by the hydrothermal method. We show the importance of nonmagnetic monovalence ions at the BI site (Na/Ag) in facilitating the superexchange interaction via orbital hybridization, offering the tunability of the Curie-Weiss parameters between -27 and -210 K, with a potential to promote magnetic frustration via alloying the nonmagnetic BI site (Ag:Na ratio). Combining our experimental evidence with first-principles calculations, we draw a cohesive picture of the material design for B-site-ordered antiferromagnetic halide double perovskites.

Topological Spin Textures in an Insulating van der Waals Ferromagnet.

Generation and control of topological spin textures constitutes one of the most exciting challenges of modern spintronics given their potential applications in information storage technologies. Of particular interest are magnetic insulators, which due to low damping, absence of Joule heating and reduced dissipation can provide energy-efficient spin-textures platform. Here, it is demonstrated that the interplay between sample thickness, external magnetic fields, and optical excitations can generate a prolific paramount of spin textures, and their coexistence in insulating CrBr3 van der Waals (vdW) ferromagnets. Using high-resolution magnetic force microscopy and large-scale micromagnetic simulation methods, the existence of a large region in T-B phase diagram is demonstrated where different stripe domains, skyrmion crystals, and magnetic domains exist and can be intrinsically selected or transformed to each-other via a phase-switch mechanism. Lorentz transmission electron microscopy unveils the mixed chirality of the magnetic textures that are of Bloch-type at given conditions but can be further manipulated into Néel-type or hybrid-type via thickness-engineering. The topological phase transformation between the different magnetic objects can be further inspected by standard photoluminescence optical probes resolved by circular polarization indicative of an existence of exciton-skyrmion coupling mechanism. The findings identify vdW magnetic insulators as a promising framework of materials for the manipulation and generation of highly ordered skyrmion lattices relevant for device integration at the atomic level.

Simulating selected magnetic properties of Tb x Pr1− x Al2, a magnetocaloric compound

Tb x Pr1−x Al2 are ferrimagnetic materials exhibiting magnetocaloric effect that have gained considerable attention due to their potential use as an alternative in refrigeration, magnetic sensors and in information storage technology. Here using the mean field approach numerical simulations were conducted for x = 0.1, 0.2, 0.3, 0.4, 0.5, and 0.75, to analyze selected physical properties, such as x-ray and neutron powder diffraction, magnetization and heat capacity. The simulations successfully reproduced the experimental data providing a comprehensive characterization and improved understanding of this family of compound.

Endohedral metallofullerene molecular nanomagnets.

Magnetic lanthanide (Ln) metal complexes exhibiting magnetic bistability can behave as molecular nanomagnets, also known as single-molecule magnets (SMMs), suitable for storing magnetic information at the molecular level, thus attracting extensive interest in the quest for high-density information storage and quantum information technologies. Upon encapsulating Ln ion(s) into fullerene cages, endohedral metallofullerenes (EMFs) have been proven as a promising and versatile platform to realize chemically robust SMMs, in which the magnetic properties are able to be readily tailored by altering the configurations of the encapsulated species and the host cages. In this review, we present critical discussions on the molecular structures and magnetic characterizations of EMF-SMMs, with the focus on their peculiar molecular and electronic structures and on the intriguing molecular magnetism arising from such structural uniqueness. In this context, different families of magnetic EMFs are summarized, including mononuclear EMF-SMMs wherein single-ion anisotropy is decisive, dinuclear clusterfullerenes whose magnetism is governed by intramolecular magnetic interaction, and radical-bridged dimetallic EMFs with high-spin ground states that arise from the strong ferromagnetic coupling. We then discuss how molecular assemblies of SMMs can be constructed, in a way that the original SMM behavior is either retained or altered in a controlled manner, thanks to the chemical robustness of EMFs. Finally, on the basis of understanding the structure-magnetic property correlation, we propose design strategies for high-performance EMF-SMMs by engineering ligand fields, electronic structures, magnetic interactions, and molecular vibrations that can couple to the spin states.

Circular dichroism in two-dimensional BC6N and B3C2N3 in absence of intervalley excitonic coupling

Two-dimensional (2D) noncentrosymmetric systems offer potential opportunities for exploiting the valley degrees of freedom for advanced information processing, owing to non-zero Berry curvature. However, such valley polarization in 2D materials is crucially governed by the intervalley excitonic scattering in momentum space due to reduced electronic degrees of freedom and consequent enhanced electronic correlation. Here, we study the valley excitonic properties of two 2D noncentrosymmetric complementary structures, namely, BC6N and B3C2N3 using first principles-based GW calculations combined with the Bethe–Salpeter equation, that brings the many-body interactions among the quasiparticles. The k-resolved oscillator strength of their first bright exciton indicates their ability to exhibit valley polarization under the irradiation of circularly polarized light of different chiralities. Both the systems show significant singlet excitonic binding energies of 0.74 eV and 1.31 eV, respectively. Higher stability of dark triplet excitons as compared to the singlet one can lead to higher quantum efficiency in both the systems. The combination of large excitonic binding energies and the valley polarization ability with minimal intervalley scattering make them promising candidates for applications in advanced optical devices and information storage technologies.

Chemo-Triggered luminescence of sulfur nanoparticles for highly secure information storage

Most of the information storage technologies that rely solely on the luminous signals of specific materials may be cracked and forged. It is always a technical challenge that special “keys” are used to trigger luminescent material for encryption. In this paper, green fluorescent quantum dots (green SQDs) were synthesized by utilizing the corrosion and encapsulation functions of polyethyleneimine (PEI). Green SQDs transform into blue SQDs under the stimulation of H2O2. Stimulus-responsive characterization of green SQDs was used for highly secure message encryption. This work provides a promising application in the field of high-security information storage for chem-triggered luminescent materials.

Research and design of student archives management system based on consortium blockchain

Student archives are records of students’ learning activities during school and important proof of students’ learning experiences, so the construction of a credible digital archives system is of great significance. Blockchain is a data structure and information storage technology that has become well-known with the development of Bitcoin and is currently widely used to build a trusted digital environment. The use of blockchain technology can solve the problems of low confidentiality and easy tampering of traditional archives management. Therefore, this paper proposes a blockchain-based student archives management scheme, designs the key data structures and algorithms of the system model, and tests the functions and performance of the system model on the ESXi platform. Experimental results show that the scheme proposed in this paper can effectively improve the confidentiality and difficulty of archive tampering, and at the same time have good resource sharing and retrieval efficiency, making archives management safer, more credible and more intelligent.

System construction of deep learning AI cloud service mode

Deep learning (DL) is the basis of many applications of artificial intelligence (AI), and cloud service is the main way of modern computer capabilities. DL functions provided by cloud services have attracted great attention. At present, the application of AI in various fields of life is gradually playing an important role, and the demand and enthusiasm of governments at all levels for building AI computing capacity are also growing. The AI logic evaluation process is often based on complex algorithms that use or generate large amounts of data. Due to the higher requirements for the data processing and storage capacity of the device itself, which are often not fully realized by humans because the current data processing technology and information storage technology are relatively backward, this has become an obstacle to the further development of AI cloud services. Therefore, this paper has studied the requirements and objectives of the cloud service system under AI by analyzing the operation characteristics, service mode and current situation of DL, constructed design principles according to its requirements, and finally designed and implemented a cloud service system, thereby improving the algorithm scheduling quality of the cloud service system. The data processing capacity, resource allocation capacity and security management capacity of the AI cloud service system were superior to the original cloud service system. Among them, the data processing capacity of AI cloud service system was 7.3% higher than the original cloud service system; the resource allocation capacity of AI cloud service system was 6.7% higher than the original cloud service system; the security management capacity of AI cloud service system was 8.9% higher than the original cloud service system. In conclusion, DL plays an important role in the construction of AI cloud service system.

How to Create Business Value Through Technological Innovations Using ICCT Underlying Technologies

Purpose: Organizations are struggling to sustain and grow in the 21st century due to many challenges and uncertainties while doing their business. Long-term sustaining in the business needs retaining the existing customers and attracting new customers through various strategies for satisfying, delighting, and enlightening existing customers, and creating overwhelming demand through business value creation for attracting new customers. It is a challenge for all the decision-makers to find out how to create business value to retain existing customers and attract new customers. Here, a conceptual and exploratory analysis is made of how the innovations using technology create business value for organizations in general. Methodology: This conceptual analysis uses an exploratory research method. The information is collected using Google, Google Scholar, and Artificial Intelligence GPT search engines using appropriate keywords and prompt engineering respectively and the collected, analysed, compared, evaluated, and interpreted towards creating business value using technology with special emphasis on the use of ICCT underlying technologies. The advantages, benefits, constraints, and disadvantages of business value creation using ICCT underlying technologies for business value creation are listed from stakeholders’ points of view. Outcome: The role of twelve ICCT Underlying Technologies including AI, Blockchain, Business intelligence, Cloud computing, Cyber security, 3D printing, IoT, Quantum computing, Mobile marketing, Information storage technology, Ubiquitous education technology, and VR & AR for Business Value Creation like Innovation and Differentiation, Customer focus, Operational efficiency, Strategic Partnerships and Alliances, Talent Management, Effective Marketing and Branding, Financial Performance and Growth, Sustainability and Corporate Social Responsibility, and Adaptability and Agility. Originality/Value: New knowledge and interpretation are presented on how to create business value for long time sustainability by organizations in every industry. Type o Paper: Exploratory Research Analysis

Octahedron distortion-triggered dipole–spin interaction in multiferroic magnetoelectric perovskites

The design of perovskite structures with multiferroic magnetoelectric coupling effects opens up new opportunities in fields such as the creation of next-generation spin-dependent multistate information storage technologies. In this work, we prepared a transition metal-implanted perovskite with multiferroic magnetoelectric coupling, in which both magnetoelectric coupling and a blueshift of photoluminescence were observed. The introduction of transition metal-generated polarized spin interacts with the electronic orbit through spin–orbital coupling to lead to a pronounced octahedron distortion, where the temperature dependence of the dielectric constant undergoes a ferroelectric polarization transition. An external magnetic field could enhance the strength of spin polarization to further affect the magnitude of electric polarization. Moreover, applying an electric field tunes the distortion of the octahedron dependence of electric polarization to feed back to the change in spin polarization. Overall, the spin polarization-induced electric polarization in perovskites provides a unique approach to realizing the room-temperature magnetoelectric coupling of multiferroic materials.

Interfacial electronic structure modulated magnetic properties in Ta/CoFeB/Ta multilayers

Thinfilm heterostructure Ta/CoFeB/TaOx can exhibit chiral magnetic textures such as skyrmions as well as spin-orbit torque induced zero field magnetization switching, which offers great promise for next-generation information storage technologies. Here, we provide a strong correlation between the structural and magnetic properties in as-deposited and annealed Ta (1 nm)/ CoFeB (1.5 nm)/ TaOx (1 nm) trilayer and Ta (1 nm)/ CoFeB (1.5 nm)/ Ta (t)/ CoFeB (1.5 nm)/ TaOx (1 nm)] multilayered stack with t = 0.5, 1 nm. Interestingly, x-ray reflectivity results indicate improvement in the interface quality post annealing up to 300 °C. While the thinner Ta spacer layer (0.5 nm) in the stack causes the formation of smaller interface width, the thicker Ta spacer (1 nm) results in relatively larger interface width. Annealing results in the enhancement of saturation magnetization (Ms) and uniaxial magnetic anisotropy (UMA) and the extent of variation is mostly determined by thickness of the spacer Ta layer. Magneto-optical Kerr effect measurement suggests the existence of strong two-fold UMA in the film stack with Ta spacer layer 0.5 nm, however, its strength diminishes as the Ta spacer layer thickness is increased to 1.0 nm. Furthermore, the in-depth chemical/electronic investigations using x-ray photoelectron spectroscopy technique reveal the formation of additional chemical states such as TaB and TaOB at the interfaces. Remarkably, Boron diffusion and likely oxygen migration from the Fe-oxide/Co-oxide in CoFeB to neighboring Ta layers improves the metallic nature of Fe and Co due to annealing. Note that the thicker Ta spacer has a significant impact on the chemical transformation at the interface in comparison to that of thinner Ta spacer layer. Overall, in these Ta/CoFeB multilayered stacks, the thickness of the Ta spacer layer and annealing temperature play a crucial role in controlling interface quality that eventually governs the magnetic characteristics. These results provide new insight into the interfacial electronic structure modifications which are essential for controlling DMI and stabilization of skyrmions in Ta/CoFeB multilayers for future spintronic device applications.

Revealing core-valence interactions in solution with femtosecond X-ray pump X-ray probe spectroscopy

Femtosecond pump-probe spectroscopy using ultrafast optical and infrared pulses has become an essential tool to discover and understand complex electronic and structural dynamics in solvated molecular, biological, and material systems. Here we report the experimental realization of an ultrafast two-color X-ray pump X-ray probe transient absorption experiment performed in solution. A 10 fs X-ray pump pulse creates a localized excitation by removing a 1s electron from an Fe atom in solvated ferro- and ferricyanide complexes. Following the ensuing Auger–Meitner cascade, the second X-ray pulse probes the Fe 1s → 3p transitions in resultant novel core-excited electronic states. Careful comparison of the experimental spectra with theory, extracts +2 eV shifts in transition energies per valence hole, providing insight into correlated interactions of valence 3d with 3p and deeper-lying electrons. Such information is essential for accurate modeling and predictive synthesis of transition metal complexes relevant for applications ranging from catalysis to information storage technology. This study demonstrates the experimental realization of the scientific opportunities possible with the continued development of multicolor multi-pulse X-ray spectroscopy to study electronic correlations in complex condensed phase systems.

Coherent stimulated amplification of the skyrmion breathing

Magnetic skyrmions are topological solitons and have great potential applications in next-generation spintronic devices for information storage and processing technologies. Here, we present an approach using the master equation involving the thermal noise to obtain the dynamical evolution of the skyrmion breathing based on the three-magnon scattering in a magnetic film, and develop a two-step model to obtain the approximated analytic solution. We show that the skyrmion breathing experiences a process where the thermal noise competes with the time-varying gain in the step I. Then the excited magnon number of the skyrmion breathing mode undergoes exponential growth with the evolutionary time due to the generation of negative total damping rate induced by the microwave drive field in the step II, which is referred to as coherent stimulated amplification of the skyrmion breathing. The analytic result is shown to be in good agreement with numerical calculation. We also obtain the threshold power of the coherent stimulated amplification behavior. In addition to offering insight into the nonlinear dynamics of skyrmions, potential applications range from realizing skyrmion cooling to providing excitation source for PT-symmetric skyrmionic systems.

Tuned band offset in homogenous TMDs via asymmetric ferroelectric semiconductor gates toward simultaneous rectification and memory

Band alignment engineering is crucial and feasible to enrich the functionalities of van der Waals heterojunctions (vdWHs) for rectifying functions in next-generation information storage technologies. However, band alignment tunability is volatile as it needs a sustained external field to maintain the Femi level of single components, which hinders the implementation of nonvolatile functions. Here, the ferroelectric semiconducting nature of alpha-In2Se3 is utilized to design vdWHs based on two-dimensional transition metal dichalcogenides (TMDs)/alpha-In2Se3, where TMDs are used as the channel, and the ferroelectric semiconductor alpha-In2Se3 is assembled as an asymmetric gate. A density functional theory validates that the band offset in a homogeneous TMDs channel is tuned by coupling the effect of the semiconducting nature and asymmetric ferroelectric gate of alpha-In2Se3, which induces simultaneous rectifying and memory functions. This includes a programmable rectifying ratio of up to 104, ultra-large memory window (110 V), programming/erasing of 104, and good endurance. The tuned band offset from the asymmetric ferroelectric semiconductor gate is conceptualized as a guideline to realize a simultaneous rectifying and memory device with high programmability.

Electric field control of magnetic states in ferromagnetic-multiferroic nanostructures.

Multiferroic oxides are considered as key elements of energy-consuming devices required for the development of scalable logic and information storage technologies. In this regard, understanding the mechanisms of magnetoelectric switching and finding the optimal way to switch magnetization by an electric field is of crucial importance. In this study, we develop a model for studying magnetic states in a nanoscale exchange-coupled ferromagnetic-multiferroic heterostructure subjected to the action of an electric field. Based on bias effects emerging due to the coupling between a ferromagnetic subsystem and an antiferromagnetically ordered multiferroic material, we explore the magnetic textures and the magnetization reversal processes in a ferromagnet. As the multiferroic material, we consider BiFeO3, where magnetic ordering and ferroelectric ordering are determined by the mutually perpendicular antiferromagnetic (L), weak ferromagnetic (M) and polarization (P) vectors. Application of an electric voltage removes degeneration from eight energetically equivalent positions of P|| 〈111〉, allocates the definite directions of vectors P, M, and L and as a consequence the unidirectional magnetic anisotropy axis in the reference ferromagnetic layer. Our study reveals the features of the magnetic configurations in systems of different geometries, with varying exchange and magnetic anisotropy, necessary to determine the optimal conditions for switching magnetic states in a multiferroic bi-layer by an electric field.

DETERMINANTS OF MARGIN AND INCOME DISPARITY AMONG PEARL MILLET TRADERS

This study analyzed the determinants of market margin and income disparity among Pearl Millet traders at Tilden Fulani Main Market, Toro, Bauchi State, Nigeria. A multistage technique was used to collect data from 90 respondents. Descriptive statistics, Market margin and efficiency ratio, regression analysis and Gini Coefficient index were analytical techniques adopted. The mean age, years spent in school, household size, trading experience and quantity of bags sold were 39 years, 6 years, 8 people, 10 years and 4 bags per month respectively. The market margin and efficiency index were ₦5,200 and 0.30 respectively. The highest volume of produce net sales was Channel 3 (29%). The regression coefficient (R2) was 0.707; implying that marketing margin variations were attributable to factors in the econometric model. The index of Gini coefficient was 0.51. The constraints of Pearl Millet marketing include inadequate capital (83.3%), transportation cost (78.9%), price information (61.1%), poor infrastructures (46.7%), storage facilities (33.3%), price volatility (27.8%) and exploitation by middlemen/ agents (17.8%). This study recommends improved access to credit and capital, subsidizing marketing costs, adoption of information communication and storage technologies; provision of market infrastructure and interventions, improved transportation; regulation of commodity prices and activities of middlemen; policy modifications.

ПОРІВНЯННЯ АЛГОРИТМІВ КЛАСИФІКАЦІЇ BIG DATA МЕТОДАМИ ІМІТАЦІЙНОГО МОДЕЛЮВАННЯ

With the development of information transmission and storage technologies, the volumes of data that require processing and analysis are growing rapidly. Therefore, the task of developing algorithms for solving various artificial intelligence problems for Big Data volumes is urgent. In our works, this informal term "Big Data" refers to situations when known processing algorithms do not allow solving a problem in a practically acceptable time. With regard to classification tasks, such conditions are possible when the first place is not even high reliability (that is, the minimum number of errors), but productivity (classification speed). The well-known method of nearest neighbors is one of the most productive. However, the indicator of the order of growth (the number of typical operations) for it is K x M x N, where K is the number of nearest neighbors, M is the number of classes, N is the typical number of class elements. Along with this, we propose to consider algorithms based on the principles of M-means, where classes are replaced by only a small number of their characteristics. Among such algorithms, the article considers: the algorithm of class centers and the algorithm of adaptive rules. The order of growth for these algorithms is only M according to the number of classes. The comparative analysis of these algorithms is performed by the method of simulation modeling. Simulation models are implemented by the Adaptive Metrics program, developed at the Department of Software Engineering at DUITZ. In this program, the classification problem is solved using the example of the dichotomy problem for classes A and B. The program has the possibility of very flexible setting of models. Problems can be solved in 1-dimensional, 2-dimensional,..., 6-dimensional spaces. The distribution of factor values for classes A and B can have quite different statistical characteristics - from uniform and triangular distribution functions to functions approaching a normal distribution. The graphical interface of the program allows you to dynamically observe the solution of the classification problem in one-dimensional, two-dimensional and 6-dimensional projections. As a result of multiple runs of the program, it was established that the algorithms of the nearest neighbors slightly outperform the algorithms of class centers and adaptive rules according to the criterion of reliability, and also comply with the principle of compactness (concentration of the largest number of erroneous solutions in the hypercube of errors). Algorithms based on M-means principles significantly outperform this algorithm in terms of performance. Also, the algorithm of adaptive rules best corresponds to the principle of equality of classes and is the most productive of the considered ones.

Efficiency Management of Electronic Communication Information Storage in Multithreaded Networks

The emergence of the Internet has brought revolutionary changes to modern information technology. The development of electronic communication information storage technology facilitates people to access information anytime and anywhere, effectively achieving resource sharing. However, traditional methods scatter communication information to all nodes, but neglect the extraction of electronic communication information association features, resulting in low information storage efficiency. This article analyzes the efficiency management of electronic communication information storage in multi-threaded networks and sets up a control experiment. Comparing the method proposed in this article with traditional methods, this study focuses on five aspects: information redundancy storage, information space utilization, productivity, data accuracy, and data transmission efficiency. It is concluded that the average information redundancy storage capacity of traditional electronic information storage methods is 8.35 x 107 T which is 6 x 107 T higher than using multi wire network electronic communication information storage methods. It indicates that traditional redundant information occupies a large amount of storage space, and its storage value exceeds the upper limit of electronic communication information storage. This means that the stored information may be overwritten by redundant information, resulting in the loss of stored information. The experimental results show that using the method proposed in this paper for electronic communication information storage results in a high distribution density of storage space and a significant improvement in information storage efficiency.

Multiple Light Source-Excited Organic Manganese Halides for Water-Jet Rewritable Luminescent Paper and Anti-Counterfeiting.

Rewritable luminescent paper is particularly crucial, considering the ultrahigh paper consumption and confidential information security, but a highly desirable stimuli-responsive smart luminescent material with excellent water solubility has rarely been studied. Herein, a new type of rewritable paper made by highly efficient green light emissive zero-dimensional (0D) organic manganese halides is rationally designed by virtue of the reversible photoluminescence (PL) off-on switching. Specifically, the green emission can be linearly quenched by water vapor in a wide humidity range and again recovered in a dry atmosphere, which make it a smart hydrochromic PL off-on switching and humidity sensor. Benefiting from the reversible luminescence off-on switch and excellent water solubility, rewritable luminescent paper is realized through water-jet security printing technology on 0D halide-coated commercial paper with high resolution. The printed/written information can be easily cleaned by slight heating with outstanding "write-erase-write" cycle capabilities. In addition, multiple light source-induced coincident green light emissions further provide convenience to realize anti-counterfeiting, encryption and decryption of confidential information, and so forth. This work highlights the superiority of dynamic ionic-bonded 0D organic manganese halides as reversible PL switching materials in rewritable luminescent paper, high-security-level information printing, storage and protection technologies, and so forth.