Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets would be suitable for use as sensors, data storage devices or in a quantum computer, since the two-dimensional arrangement allows the magnification state of the individual atoms or molecules to be selected. For mathematical and geometrical reasons, however, it has so far not been possible to produce two-dimensional ferrimagnets.
Choice of materials makes the impossible possible
The scientists in Professor Thomas Jung’s research groups at the Paul Scherrer Institute (PSI) and the Department of Physics at the University of Basel have now found a method of making a two-dimensional ferrimagnet.
The researchers first produce “phthalocyanines” – hydrocarbon compounds with different magnetic centers composed of iron and manganese. When these phthalocyanines are applied to a gold surface, they arrange themselves into a checkerboard pattern in which molecules with iron and manganese centers alternate. The researchers were able to prove that the surface is magnetic, and that the magnetism of the iron and manganese is of different strengths and appears in opposing directions – all characteristics of a ferrimagnet.
“The decisive factor of this discovery is the electrically conductive gold substrate, which mediates the magnetic order,” explains Dr. Jan Girovsky from the PSI, lead author of the study. “Without the gold substrate, the magnetic atoms would not sense each other and the material would not be magnetic.”
The decisive effect of the conducting electrons in the gold substrate is shown by a physical effect detected in each magnetic atom using scanning tunnel spectroscopy. The experiments were conducted at various temperatures and thus provide evidence of the strength of the magnetic coupling in the new magnetic material. Model calculations confirmed the experimentally observed effect and indicated that special electrons attached to the surface in the gold substrate are responsible for this type of magnetism.
Nanoarchitecture leads to new magnetic materials
“The work shows that a clever combination of materials and a particular nanoarchitecture can be used to produce new materials that otherwise would be impossible,” says Professor Nirmalya Ballav of the Indian Institute of Science Education and Research in Pune (India), who has been studying the properties of molecular nano-checkerboard architectures for several years with Jung. The magnetic molecules have great potential for a number of applications, since their magnetism can be individually investigated and also modified using scanning tunnel spectroscopy.
Jan Girovsky, Jan Nowakowski, Md. Ehesan Ali, Milos Baljozovic, Harald R. Rossmann, Thomas Nijs, Elise A. Aeby, Sylwia Nowakowska, Dorota Siewert, Gitika Srivastava, Christian Wackerlin, Jan Dreiser, Silvio Decurtins, Shi-Xia Liu, Peter M. Oppeneer, Thomas A. Jung and Nirmalya Ballav
Long-range ferrimagnetic order in a two-dimensional supramolecular Kondo lattice
Nature Communications (2017), doi: 10.1038/ncomms15388
Prof. Dr. Thomas A. Jung, University of Basel, Swiss Nanoscience Institute, tel. +41 56 310 45 18, email: email@example.com
Reto Caluori | Universität Basel
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Life Sciences
18.07.2018 | Life Sciences
18.07.2018 | Information Technology