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FURORE — Result In Brief

Project ID: 226180
Funded under: FP7-IDEAS-ERC
Country: Germany

New research explores the magnetism of single atoms

An EU-funded project took a clearer look at the magnetic interactions and properties of single atoms that can be candidates for miniaturised data storage and spintronic devices for the implementation of quantum computing.
New research explores the magnetism of single atoms
Within the project FURORE (Fundamental studies and innovative approaches of research on magnetism), researchers used innovative experimental approaches to study the individual magnetic properties of single atoms on metal and semiconductor surfaces.

The project team demonstrated the ability to measure magnetisation response of individual magnetic atoms (iron) adsorbed on a non-magnetic substrate (copper) with use of a scanning tunnelling microscope with a spin-polarised tip. Following detailed characterisation of these distance-dependent interactions that caused pairs of iron atoms to either align or anti-align to the tip magnetisation depending on their atomic spacing, the team constructed a roadmap of the magnetic interactions. The study of the magnetic interactions from single-atom magnetisation curves suggests that in the future single atoms may be utilised for storing information in devices.

Using the spin-polarised scanning tunnelling microscopy (SP-STM) method, project members successfully built complex artificial magnetic nanostructures. The newly formed iron linear chains and spin frustrated nanostructures showed the ability to be combined with ferromagnetic islands, thereby realising an all-spin logic gate on the atomic level.

Researchers then used a technique called inelastic electron tunnelling spectroscopy (IETS) to probe the quantum spin states of a single iron atom bound to copper, silver or platinum layers. The technique uses an atom-sized scanning tip that allows the passage of electrons to the bound iron atom. Electrons tunnelling through transferred energy to the iron atom, inducing changes in the iron spin properties.

This experiment showed that the conduction electron cloud of the substrate plays a major role in limiting the lifetime of the iron spin excitations. Researchers also combined SP-STM and IETS to reveal the current-driven spin dynamics of artificially constructed quantum magnets consisting of a few atoms only.

Two complementary techniques were used to read out the magnetisation curve and measure the magnetic excitations of single dopant atoms bound to semiconductors. Results showed that a magnetic dopant atom can serve as an atomic-sized magnetometer for measuring magnetisation of the electron cloud on the semiconductor surface.

Project members pioneered an experimental method called magnetic exchange force spectroscopy, which allows quantitative measuring of the strength of the magnetic exchange interaction between single spin states of the magnetic tip and the sample atoms across a vacuum gap. Experimental activities were complemented by theoretical studies on energy loss mechanisms between the tip and the sample.

FURORE's pioneering research on single-atom magnetisation curves and magnetic interactions is crucial to the development of novel devices with increased storage capacity and efficiency.

Related information


Magnetism, single atoms, magnetic interactions, quantum computing, FURORE
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