The discovery of magnetization switching via spin transfer torque (STT) in PMA-based MTJs has led to the development of next-generation magnetic memory technology with high operating speed, low power consumption and high scalability. In this work, we theoretically investigate the influence of finite size and temperature on the mechanism of magnetization switching in CoFeB-MgO based MTJ to get better understanding of STT-MRAM fundamentals and design. An atomistic model coupled with simultaneous solution of the spin accumulation is employed. The results reveal that the incoherent switching process in MTJ strongly depends on the system size and temperature. At 0 K, the coherent switching mode can only be observed in MTJs with the diameter less than 20 nm. However, at any finite temperature, incoherent magnetization switching is thermally excited. Furthermore, increasing temperature results in decreasing switching time of the magnetization. We conclude that temperature dependent properties and thermally driven reversal are important considerations for the design and development of advanced MRAM systems.
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http://dx.doi.org/10.1038/s41598-023-29597-7 | DOI Listing |
ACS Nano
January 2025
Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada.
Theory and simulations are used to demonstrate implementation of a variational Bayes algorithm called "active inference" in interacting arrays of nanomagnetic elements. The algorithm requires stochastic elements, and a simplified model based on a magnetic artificial spin ice geometry is used to illustrate how nanomagnets can generate the required random dynamics. Examples of tracking and PID control are demonstrated and shown to be consistent with the original stochastic differential equation formulation of active inference.
View Article and Find Full Text PDFNano Lett
January 2025
Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
Realizing field-free switching of perpendicular magnetization by spin-orbit torques is crucial for developing advanced magnetic memory and logic devices. However, existing methods often involve complex designs or hybrid approaches, which complicate fabrication and affect device stability and scalability. Here, we propose a novel approach using -polarized spin currents for deterministic switching of perpendicular magnetization through interfacial engineering.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588-0299, United States.
A spin valve represents a well-established device concept in magnetic memory technologies, whose functionality is determined by electron transmission, controlled by the relative alignment of magnetic moments of the two ferromagnetic layers. Recently, the advent of valleytronics has conceptualized a valley spin valve (VSV)─a device that utilizes the valley degree of freedom and spin-valley locking to achieve a similar valve effect without relying on magnetism. In this study, we propose a nonvolatile VSV (-VSV) based on a two-dimensional (2D) ferroelectric semiconductor where resistance of -VSV is controlled by a ferroelectric domain wall between two uniformly polarized domains.
View Article and Find Full Text PDFFood Chem
January 2025
School of Food and Biological Engineering, Key Laboratory for Animal Food Green Manufacturing and Resource Mining of Anhui Province, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology, Hefei 230009, China. Electronic address:
Ultra-precision point-of-care detection of Escherichia coli O157:H7 in foods is an important issue. Here, the detection sensitivity was improved by a signal cascade amplification strategy synergised by exonuclease III assisted isothermal amplification and reverse magnetic strategy. The double-stranded DNA formed by the aptamer and the target DNA as a sensing switch, avoiding the complex process of specific nucleic acid extraction.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
The integration of spin crossover (SCO) magnetic switching and electric polarization properties can engender intriguing correlated magnetic and electric phenomena. However, achieving substantial SCO-induced polarization change through rational molecular design remains a formidable challenge. Herein, we present a polar Fe(II) compound that exhibits substantial polarization change in response to a thermally regulated low-spin ↔ high-spin transition.
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