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Giant multiferroic effects in topological GeTe-Sb 2 Te 3 superlattices

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ABSTRACT

Multiferroics, materials in which both magnetic and electric fields can induce each other, resulting in a magnetoelectric response, have been attracting increasing attention, although the induced magnetic susceptibility and dielectric constant are usually small and have typically been reported for low temperatures. The magnetoelectric response usually depends on d-electrons of transition metals. Here we report that in [(GeTe)2(Sb2Te3)l]m superlattice films (where l and m are integers) with topological phase transition, strong magnetoelectric response may be induced at temperatures above room temperature when the external fields are applied normal to the film surface. By ab initio computer simulations, it is revealed that the multiferroic properties are induced due to the breaking of spatial inversion symmetry when the p-electrons of Ge atoms change their bonding geometry from octahedral to tetrahedral. Finally, we demonstrate the existence in such structures of spin memory, which paves the way for a future hybrid device combining nonvolatile phase-change memory and magnetic spin memory.

No MeSH data available.


I–V curves from the iPCM-SET phase with and without a magnetic field (2 kOe and 4 kOe) for the spin-storage device (inset) at room temperature, using iPCM [(GeTe)2(Sb2Te3)4]8.
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Figure 7: I–V curves from the iPCM-SET phase with and without a magnetic field (2 kOe and 4 kOe) for the spin-storage device (inset) at room temperature, using iPCM [(GeTe)2(Sb2Te3)4]8.

Mentions: Figure 7 shows I–V curves for this structure (shown in the inset) SET either with or without a magnetic field. The curves shown clearly demonstrate a magnetoresistance response depending on the strength of the magnetic field. In particular, at intermediate field strength (2 kOe), an I–V curve with several steps was observed, which supports practical applicability for multilevel magnetoresistance memory devices.


Giant multiferroic effects in topological GeTe-Sb 2 Te 3 superlattices
I–V curves from the iPCM-SET phase with and without a magnetic field (2 kOe and 4 kOe) for the spin-storage device (inset) at room temperature, using iPCM [(GeTe)2(Sb2Te3)4]8.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036496&req=5

Figure 7: I–V curves from the iPCM-SET phase with and without a magnetic field (2 kOe and 4 kOe) for the spin-storage device (inset) at room temperature, using iPCM [(GeTe)2(Sb2Te3)4]8.
Mentions: Figure 7 shows I–V curves for this structure (shown in the inset) SET either with or without a magnetic field. The curves shown clearly demonstrate a magnetoresistance response depending on the strength of the magnetic field. In particular, at intermediate field strength (2 kOe), an I–V curve with several steps was observed, which supports practical applicability for multilevel magnetoresistance memory devices.

View Article: PubMed Central - PubMed

ABSTRACT

Multiferroics, materials in which both magnetic and electric fields can induce each other, resulting in a magnetoelectric response, have been attracting increasing attention, although the induced magnetic susceptibility and dielectric constant are usually small and have typically been reported for low temperatures. The magnetoelectric response usually depends on d-electrons of transition metals. Here we report that in [(GeTe)2(Sb2Te3)l]m superlattice films (where l and m are integers) with topological phase transition, strong magnetoelectric response may be induced at temperatures above room temperature when the external fields are applied normal to the film surface. By ab initio computer simulations, it is revealed that the multiferroic properties are induced due to the breaking of spatial inversion symmetry when the p-electrons of Ge atoms change their bonding geometry from octahedral to tetrahedral. Finally, we demonstrate the existence in such structures of spin memory, which paves the way for a future hybrid device combining nonvolatile phase-change memory and magnetic spin memory.

No MeSH data available.