Friday, July 3, 2020
US researchers have manipulated fixed magnetic skyrmions using voltages, offering a possible route to skyrmion memory.
Magnetic skyrmions are self-contained stable spin fields that share some characteristics with particles. They can be only a few nanometres across, and in certain circumstances can be created, destroyed and manipulated with very little energy, leading to them being studied as a possible memory technology.
They have been moved with current to store data and, last year, Japanese, Chinese and Singaporean scientists created and moved them 10µm with voltage – a process using less energy and less likely to damage the skyrmions using current, according to that team.
Working with the University of California, Los Angeles, scientists at Virginia Commonwealth University have found a way to fix positions for skyrmions, then create or delete them.
“Our finding demonstrates the possibility of controlling skyrmion states using electric fields, which could ultimately lead to more compact, energy efficient nanomagnetic devices,” said VCU engineer Dhritiman Bhattacharya.
According to the VCU-UCLA paper ‘Creation and annihilation of non-volatile fixed magnetic skyrmions using voltage control of magnetic anisotropy’, published in Nature Electronics, the fixed magnetic skyrmions, stabilised in antiferromagnet-ferromagnet-oxide heterostructure films – without any external magnetic field – as the title explains, manipulated using voltage-controlled magnetic anisotropy.
The isolated skyrmions are annihilated or formed by applying voltage pulses that increase or decrease the perpendicular magnetic anisotropy, respectively.
In 2016 and 2018, the VCU researchers showed that using an intermediate skyrmion state to force precise magnetic transitions between the “up” and “down” state could reduce errors in writing information to memory, making devices more robust to material defects and thermal noise. They hold a patent on this idea. The proof-of-concept experiment described in Nature Electronics is the first step toward making such a device.
‘Creation and annihilation of non-volatile fixed magnetic skyrmions using voltage control of magnetic anisotropy’ is available here – abstract only without paying.
The 2019 work by Shinsu University, Chinese University of Hong Kong, University of Tokyo, Tsinghus University , Kyoto University and Nanyang Technalogical University is outlined in this video, which also has an introduction to magnetic skyrmions.
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