Visualization was enabled by designing a new artificial magnetic material. The finding means remarkable possibilities to materials research.
Researchers at Aalto University and Lawrence Berkeley National Laboratory have demonstrated that polaron formation also occurs in a system of magnetic charges, and not just in a system of electric charges. Being able to control the transport properties of such charges could enable new devices based on magnetic rather than electric charges, for example computer memories.
Polarons are an example of emergent phenomena known to occur in condensed matter physics. For instance, an electron moving across a crystal lattice displaces the surrounding ions, together creating an effective quasi-particle, a polaron, which has an energy and mass that differs from that of a bare electron. Polarons have a profound effect on electronic transport in materials.
Artificial spin ice systems are metamaterials that consist of lithographically patterned nanomagnets in an ordered two-dimensional geometry. The individual magnetic building blocks of a spin ice lattice interact with each other via dipolar magnetic fields.
Researchers used material design as a tool to create a new artificial spin ice, the dipolar dice lattice.
‘Designing the correct two-dimensional lattice geometry made it possible to create and observe the decay of magnetic polarons in real-time,’ says postdoctoral researcher Alan Farhan from Lawrence Berkeley National Laboratory (USA).
‘We introduced the dipolar dice lattice because it offers a high degree of frustration, meaning that competing magnetic interactions cannot be satisfied simultaneously. Like all systems in nature, the dipolar dice lattice aims to relax and settle into a low-energy state. As a result, whenever magnetic charge excitations emerge over time, they tend to get screened by opposite magnetic charges from the environment,’ explains Dr. Farhan.
The researchers at Berkeley used photoemission electron microscopy, or PEEM, to make the observations. This technique images the direction of magnetization in individual nanomagnets. With the magnetic moments thermally fluctuating, the creation and decay of magnetic polarons could be imaged in real space and time. Postdoctoral researcher Charlotte Peterson and Professor Mikko Alava at Aalto University (Finland) performed simulations, which confirmed the rich thermodynamic behavior of the spin ice system.
‘The experiments also demonstrate that magnetic excitations can be engineered at will by a clever choice of lattice geometry and the size and shape of individual nanomagnets. Thus, artificial spin ice is a prime example of a designer material. Instead of accepting what nature offers, it is now possible to assemble new materials from known building blocks with purposefully designed functionalities,’ says Professor Sebastiaan van Dijken from Aalto University.
‘This concept, which goes well beyond magnetic metamaterials, is only just emerging and will dramatically shape the frontier of materials research in the next decade,’ adds Professor van Dijken.
Learn more: Magnetic polaron imaged for the first time
The Latest on: Materials research
via Google News
The Latest on: Materials research
- Advanced Cold Moderators for Intense Cold Neutron Beams in Materials Researchon November 8, 2019 at 7:21 am
Neutron scattering is a set of powerful techniques for analyzing materials, ranging from biomaterials, through turbine engines, through to hard magnets. Intense sources of neutrons for this purpose ...
- NASA ISS National Lab Opportunity for Materials Researchon October 29, 2019 at 8:39 am
The International Space Station (ISS) U.S. National Laboratory has announced a Request for Proposals focused on advanced materials, in support of research with translational or applied outcomes to ...
- Institute for Materials Researchon September 29, 2019 at 5:00 pm
The Institute for Materials Research - 2.0 (IMR - 2.0) is an Organized Research Center at Binghamton University (BU) that offers expertise and facilities in the field of materials science to faculty ...
- XVIII Brazil Materials Research Society Meeting.on September 22, 2019 at 6:00 am
The annual meeting of the Brazilian MRS is an international and interdisciplinary forum dedicated to recent advances and perspectives in materials science and technology. In recent editions, the ...
- New method for material research gets hundred times strongeron September 10, 2019 at 6:59 am
Researchers from the Faculty of Science at the University of Oulu have increased the sensitivity of an emerging spectroscopic method with promising applications for materials studies. The NMR Research ...
- New method for material research gets hundred times strongeron September 10, 2019 at 3:13 am
The ultimate aim of the NMO research is to provide high-sensitivity optical data with atomic-resolution about the studied material. It is crucial to improve the spectroscopic sensitivity, so that ...
- $14 million grant to expand chemistry and materials research capabilities at Argonne National Labon August 8, 2019 at 8:17 am
Mark Schlossman, professor of physics at the University of Illinois at Chicago, has received a $14.1 million, five-year grant from the National Science Foundation to expand the experimental ...
- Materials Research Societyon July 30, 2019 at 5:00 pm
The Materials Research Society (MRS) is an organization of materials researchers worldwide that promotes communication for the advancement of interdisciplinary materials research and technology to ...
- Pathways to Energy from Inertial Fusion: Materials Research and Technology Developmenton July 10, 2019 at 5:00 pm
This CRP seeks to advance the fundamental fusion-material research and -technologies, in close connection with high gain target development, and enhance information exchange on Inertial Fusion Energy ...
via Bing News