Communications of the ACM
New Options For Spintronic Devices: Switching Between 1 and 0 With Low Voltage
A thin magnetic FeRh film is grown onto a ferroelastic BTO substrate with two different crystal domains a and c. At 0 Volt ferromagnetic domains (red-blue pattern) are observed above BTO a-domains, whereas above c-domains the net magnetization is zero. At
Credit: HZB
Helmholtz-Zentrum Berlin (HZB) and French researchers have demonstrated switching ferromagnetic domains on and off with low voltage at slightly above room temperature in a structure made of two different ferroic materials.
The researchers say the breakthrough could lead to future applications in low-power spintronics, which can be used for fast, efficient data storage.
The structure consists of a ferroelastic BTO substrate on which a thin film of ferromagnetic FeRh was grown. "We could switch ferromagnetic states in the FeRh film completely on and off with a low voltage applied to the underlaying BTO," says HZB researcher Sergio Valencia. The researchers used XPEEM imaging to observe the transition between different magnetic orders in the FeRh layer, driven by an electrical field applied across the BTO substrate.
The researchers say the technique works because a low voltage on the BTO substrate deforms its crystal structure via a ferroelastic effect, creating a strain, which is then transferred to the FeRh film, influencing its magnetic order. "When the voltage was applied to the BTO substrate, the strain transferred from BTO to the FeRh increased the temperature needed to have a ferromagnetic order and the FeRh became antiferromagnetic," Valencia says.
The researchers next plan to dope the FeHr film with palladium, which should get the effects even closer to room temperature.
From Helmholtz-Zentrum Berlin
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