As advances in computing technology increase demand for efficient data storage solutions, spintronic magnetic tunnel junction (MTJ)-based magnetic random-access memory (MRAM) devices emerge as promising alternatives to traditional charge-based memory devices. Successful applications of such spintronic devices necessitate understanding not only their ideal working principles but also their breakdown mechanisms. Employing an in situ electrical biasing system, atomic-resolution scanning transmission electron microscopy (STEM) reveals two distinct breakdown mechanisms. Soft breakdown occurs at relatively low electric currents due to electromigration, wherein restructuring of MTJ core layers forms ultrathin regions in the dielectric MgO layer and edge conducting paths, reducing device resistance. Complete breakdown occurs at relatively high electric currents due to a combination of joule heating and electromigration, melting MTJ component layers at temperatures below their bulk melting points. Time-resolved, atomic-scale STEM studies of functional devices provide insight into the evolution of structure and composition during device operation, serving as an innovative experimental approach for a wide variety of electronic devices.
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http://dx.doi.org/10.1021/acsnano.4c08023 | DOI Listing |
ACS Nano
January 2025
Department of Physics, University of Basel, Klingelbergstrasse 82, Basel 4056, Switzerland.
Flat bands in Kagome graphene might host strong electron correlations and frustrated magnetism upon electronic doping. However, the porous nature of Kagome graphene opens a semiconducting gap due to quantum confinement, preventing its fine-tuning by electrostatic gates. Here we induce zero-energy states into a semiconducting Kagome graphene by inserting π-radicals at selected locations.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
Department of Computer Engineering, Modeling, Electronics, and Systems Engineering, University of Calabria, 87036 Rende, Italy.
This paper presents Cryo-SIMPLY, a reliable smart material implication (SIMPLY) operating at cryogenic conditions (77 K). The assessment considers SIMPLY schemes based on spin-transfer torque magnetic random access memory (STT-MRAM) technology with single-barrier magnetic tunnel junction (SMTJ) and double-barrier magnetic tunnel junction (DMTJ). Our study relies on a temperature-aware macrospin-based Verilog-A compact model for MTJ devices and a 65 nm commercial process design kit (PDK) calibrated down to 77 K under silicon measurements.
View Article and Find Full Text PDFInorg Chem
January 2025
School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
Air-stable single-molecule magnets (SMMs) can be obtained by confining Dy ion in a coordination environment; however, most of the current efforts were focused on modifying the rigidity of the macrocycle ligand. Herein, we attempt to assemble air-stable SMMs based on macrocycles with a replaceable coordination site. By using an in situ 1 + 1 Schiff-base reaction of dialdehyde with diamine, three air-stable SMMs have been obtained in which one of the equatorial coordination sites can be varied from -NH- (for ), -O- (for ), and -NMe- (for ).
View Article and Find Full Text PDFJ Phys Chem A
January 2025
School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
Searching for single-molecule magnets (SMM) with large effective blocking barriers, long relaxation times, and high magnetic blocking temperatures is vitally important not only for the fundamental research of magnetism at the molecular level but also for the realization of new-generation magnetic memory unit. Actinides (An) atoms possess extremely strong spin-orbit coupling (SOC) due to their 5 orbitals, and their ground multiplets are largely split into several sublevels because of the strong interplay between the SOC of An atoms and the crystal field (CF) formed by ligand atoms. Compared to TM-based SMMs, more dispersed energy level widths of An-based SMMs will give a larger total zero field splitting (ZFS) and thus provide a necessary condition to derive a higher .
View Article and Find Full Text PDFNat Mater
January 2025
Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Chirality, a basic property of symmetry breaking, is crucial for fields such as biology and physics. Recent advances in the study of chiral systems have stimulated interest in the discovery of symmetry-breaking states that enable exotic phenomena such as spontaneous gyrotropic order and superconductivity. Here we examine the interaction between light chirality and electron spins in indium selenide and study the effect of magnetic field on emerging tunnelling photocurrents at the Van Hove singularity.
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