Magnetization switching in ferromagnets by adsorbed chiral molecules without current or external magnetic field.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28230054.
- Also identified by DOI 10.1038/ncomms14567 and PMC identifier 5331337.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Ferromagnets are commonly magnetized by either external magnetic fields or spin polarized currents. The manipulation of magnetization by spin-current occurs through the spin-transfer-torque effect, which is applied, for example, in modern magnetoresistive random access memory. However, the current density required for the spin-transfer torque is of the order of 1 × 10<sup>6</sup> A·cm<sup>-2</sup>, or about 1 × 10<sup>25</sup> electrons s<sup>-1</sup> cm<sup>-2</sup>. This relatively high current density significantly affects the devices' structure and performance. Here we demonstrate magnetization switching of ferromagnetic thin layers that is induced solely by adsorption of chiral molecules. In this case, about 10<sup>13</sup> electrons per cm<sup>2</sup> are sufficient to induce magnetization reversal. The direction of the magnetization depends on the handedness of the adsorbed chiral molecules. Local magnetization switching is achieved by adsorbing a chiral self-assembled molecular monolayer on a gold-coated ferromagnetic layer with perpendicular magnetic anisotropy. These results present a simple low-power magnetization mechanism when operating at ambient conditions.