| Jul 08, 2019 | |
Unlocking magnetic properties for future faster, low-energy spintronics(Nanowerk News) A theoretical-experimental collaboration across two FLEET nodes has discovered new magnetic properties within 2D structures, with exciting potential for researchers in the emerging field of 'spintronics'. |
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| Spintronic devices use a quantum property known as 'spin', in addition to the electronic charge of conventional electronics. | |
| Spintronics thus promise ultra-high speed low-energy electronic devices with significantly enhanced functionality. | |
| The RMIT-UNSW study (Science Advances, "Antisymmetric magnetoresistance in van der Waals Fe3GeTe2/graphite/Fe3GeTe2 trilayer heterostructures") discovered never-before-seen magnetic properties in devices known as vdW hetero-structures comprising several layers of novel, 2D materials. | |
| The latest results show that vdW spintronics could provide devices with more functionality, comparing with the traditional spintronic approaches. Further research could generate devices with significant industrial applications. | |
Background |
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| Two-dimensional (2D) ferromagnetic van-der-Waals (vdW) materials have recently emerged as effective building blocks for a new generation of 'spintronic' devices. | |
| When layered with non-magnetic vdW materials, such as graphene and/or topological insulators, vdW hetero-structures can be assembled to provide otherwise unattainable device structures and functionalities. | |
| The material studied was 2D Fe3GeTe2 (FGT), a metal found to display promising ferromagnetic properties for spintronic devices in a previous FLEET study. | |
Surprising discoveries |
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| "We discovered a previously unseen mode of giant magneto-resistance (GMR) in the material, says FLEET PhD and study co-author Sultan Albarakati. | |
| Unlike the conventional, previously-known two GMR states (ie, high resistance and low resistance) that occur in thin-film hetero-structures, the researchers also measured antisymmetric GMR with an additional, distinct intermediate resistance state. | |
| "This reveals that vdW ferromagnetic hetero-structures exhibit substantially different properties from similar structures," says Sultan. | |
| This surprising result is contrary to previously held beliefs regarding GMR. It is suggestive of different underlying physical mechanisms in vdW hetero-structures, with potential for improved magnetic information storage. | |
| Theoretical calculations indicate that the three levels of resistance are the result of spin-momentum-locking induced spin-polarised current at the graphite/FGT interface. | |
| "This work has significant interest for researchers in 2D materials, spintronics, and magnetism," says co-author FLEET PhD Cheng Tan. "It means that 'traditional' tunnelling magnetoresistance devices, spin-orbit torque devices and spin transistors may reward re-investigated using similar vdW hetero-structures to reveal similarly surprising characteristics." |
| Source: ARC Centre of Excellence in Future Low-Energy Electronics Technologies | |
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