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Magnonic holographic memory is a type of memory that uses spin waves for magnetic bit read-in and read-out. Its operation is based on the interaction between magnets and propagating spin waves where the phase and the amplitude of the spin wave are sensitive to the magnetic field produced by the magnet. Memory states 0 and 1 are associated with the presence/absence of the magnet in a specific location. In this work, we present experimental data showing the feasibility of magnetic bit location using spin waves. The testbed consists of four micro-antennas covered by Y 3 Fe 2 (FeO 4 ) 3 yttrium iron garnet (YIG) film. A constant in-plane bias magnetic field is provided by NdFeB permanent magnet. The magnetic bit is made of strips of magnetic steel to maximize interaction with propagating spin waves. In the first set of experiments, the position of the bit was concluded by the change produced in the transmittance between two antennas. The minima appear at different frequencies and show different depths for different positions of the bit. In the second set of experiments, two input spin waves were generated, where the phase difference between the waves is controlled by the phase shifter. The minima in the transmitted spectra appear at different phases for different positions of magnetic bit. The utilization of the structured bit enhances its interaction with propagating spin waves and improves recognition fidelity compared to a regular-shaped bit. The recognition accuracy is further improved by exploiting spin wave interference. The depth of the transmission minima corresponding to different magnet positions may exceed 30 dB. All experiments are accomplished at room temperature. Overall, the presented data demonstrate the practical feasibility of using spin waves for magnetic bit red-out. The practical challenges are also discussed.
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This content will become publicly available on November 29, 2025
An explicitly magnetic modified embedded atom method formalism for coupled spin dynamics and molecular dynamics
Abstract In this paper, we augment the modified embedded atom method formalism to include magnetic spin–spin interactions for elements with a persistent magnetic moment. While previous spin coupling methods have been based on pair potentials, our Magnetic MEAM formalism, which we term MagMEAM, incorporates the many-body and angular effects of MEAM allowing for the strength of the magnetic interaction to vary with atomic environment. In particular, this allows potentials using this formalism to differentiate the magnetic interaction of different stable phases of magnetic elements such as the ferritic and austenitic phases of iron. This, in turn, allows for a more robust and realistic description of magnetism in polymorphic materials than was previously possible. The motivation for MagMEAM, including the insufficiency of magnetic pair potentials, is presented and the structure of the formalism is developed. A sample iron potential is developed using this formalism and shown to exceed the capabilities of existing magnetic pair potentials by simultaneously reproducing the magnetic energy of both martensite and austenite as well as the dynamic mechanical and magnetic properties of martensite. This newly designed formalism will allow for deeper explorations in the the complex interaction between different phases of polymorphic magnetic materials at the molecular dynamics scale.
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- Award ID(s):
- 2143610
- PAR ID:
- 10574847
- Publisher / Repository:
- IOP
- Date Published:
- Journal Name:
- Modelling and Simulation in Materials Science and Engineering
- Volume:
- 33
- Issue:
- 1
- ISSN:
- 0965-0393
- Page Range / eLocation ID:
- 015006
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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