Jul 16, 2024 |
(Nanowerk Information) Researchers from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), TU Chemnitz, TU Dresden and Forschungszentrum Jülich have been the primary to show that not simply particular person bits, however whole bit sequences may be saved in cylindrical domains: tiny, cylindrical areas measuring simply round 100 nanometers.
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Because the group reviews within the journal Superior Digital Supplies (“Multilayer Metamaterials with Ferromagnetic Domains Separated by Antiferromagnetic Domain Walls”), these findings may pave the way in which for novel kinds of information storage and sensors, together with even magnetic variants of neural networks.
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“A cylindrical domain, which we physicists also call a bubble domain, is a tiny, cylindrical area in a thin magnetic layer. Its spins, the electrons’ intrinsic angular momentum that generates the magnetic moment in the material, point in a specific direction. This creates a magnetization that differs from the rest of the environment. Imagine a small, cylinder-shaped magnetic bubble floating in a sea of opposite magnetization,” says Prof. Olav Hellwig from HZDR’s Institute of Ion Beam Physics and Supplies Analysis, describing the topic of his analysis. He and his group are assured that such magnetic constructions possess a fantastic potential for spintronic functions.
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Data is saved by the depth-dependent course of magnetization within the area partitions, that are situated between the cylinder domains and their environment. This magnetization of the area partitions can level clockwise or counterclockwise within the particular person blocks, that are separated vertically by ruthenium layers. By systematically various these instructions, researchers can encode totally different bit sequences inside a cylinder area, as is proven right here with some inventive interpretation. (Picture: B. Schröder / HZDR)
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Area partitions type on the edges of this cylindrical area, fringe areas wherein the course of magnetization adjustments. Within the magnetic storage know-how, which Hellwig’s group is making an attempt to attain, it is going to be essential to exactly management the spin construction within the area wall, since its clockwise or counterclockwise course can be utilized on to encode bits.
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The researchers are additionally specializing in one other side: “Our current hard disks, with their track widths of 30 to 40 nanometers and bit lengths of 15 to 20 nanometers, accommodate approximately one terabyte on a surface the size of a postage stamp. We are working to overcome this data-density limitation by extending storage into the third dimension,” Hellwig explains.
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The answer: Metamaterials in 3D
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Magnetic multilayer constructions are an interesting means of controlling the inner spin construction of area partitions as a result of the magnetic energies concerned may be adjusted by combining totally different supplies and layer thicknesses. Hellwig’s group used blocks of alternating layers of cobalt and platinum, separated by layers of ruthenium, and deposited them on silicon wafers.
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The ensuing metamaterial is an artificial antiferromagnet. Its particular characteristic is a vertical magnetization construction wherein adjoining layer blocks have reverse instructions of magnetization, leading to a web impartial magnetization total.
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“This is where the concept of the ‘racetrack’ memory comes in. The system is like a racetrack, along which the bits are arranged like a string of pearls. The ingenious thing about our system is that we can specifically control the thickness of the layers and thus, their magnetic properties. This allows us to adapt the magnetic behavior of the synthetic antiferromagnet to enable the storage not only of individual bits, but entire bit sequences, in the form of a depth-dependent magnetization direction of the domain walls,” explains Hellwig.
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This opens up the prospect of transporting such multi-bit cylinder domains alongside these magnetic information highways in a managed, quick, and energy-efficient method.
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There may be additionally potential for different functions in magnetoelectronics. As an example, they can be utilized in magnetoresistive sensors or in spintronic parts. As well as, such advanced magnetic nano-objects have nice potential for magnetic implementations in neural networks that might course of information in the identical means because the human mind.
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