A team led by the Aragon Nanoscience and Materials Institute creates the world’s thinnest hard magnet
An international team of researchers led by the Aragon Nanoscience and Materials of Institute (INMA-CSIC-UNIZAR), a joint institute of the Spanish National Research Council (CSIC) and the University of Zaragoza (UNIZAR), has created a hard magnet of atomic thickness for the first time in the world. It is the thinnest magnet that exists and will ever exist, with a defined magnetic direction, relatively high temperature and very difficult to demagnetise. After seven years of study, this finding represents a clear breakthrough in the cross-cutting research fields of magnetism and surface science, given that this is a goal that has been pursued for more than two decades by teams of scientists around the world. The results are published in the journal Nature Communications.
Fernando Bartolomé Usieto, CSIC researcher at INMA and currently Education Advisor in the United Kingdom and Ireland, and Jorge Lobo Checa, also a scientist at INMA and a leading researcher at the Laboratory of Advanced Microscopy (LMA), are the architects of this achievement: reducing a hard magnet to the minimum expression, within the current general trend towards miniaturisation, which consists of trying to obtain increasingly smaller elements that occupy as little space as possible, but without losing their properties.
“We have managed, through a combination of molecules and iron atoms, to generate a network where the atoms are separated from each other at a fixed distance and have a direction of magnetisation perpendicular to this network,” explains Lobo. The combination of materials he refers to is a molecule derived from an anthracene (three carbon rings) and iron atoms. This results in a lattice (like the structure of a honeycomb) where the iron atoms are positioned at the vertices of the hexagons.
The hardness of the magnet
The hardness of this hyperfine magnet is defined by the difficulty of reversing the direction of magnetisation. “The field that sets the hardness of a ferromagnetic material is the strength of the magnetic field that must be applied to that material to reverse its magnetisation. This indicates how hard or soft it is. And the harder it is to change the direction of magnetisation, the harder it is,” says Lobo. Bartolomé says: “The hardness of this atomically thick magnet is similar to that of neodymium magnets.
This basic science breakthrough has potential practical applications in any technological device where a magnetic field needs to be incorporated, for example, a computer’s RAM memory or a transistor. “It will be very useful for miniaturising things even further thanks to its small size. You have to take into account that in this magnet the iron atoms are separated by distances of one nanometre, that is, one millionth of a millimetre,” Lobo explains.
The work has been carried out by an international team led by INMA, with the collaboration of the Advanced Microscopy Laboratory (LMA) of the University of Zaragoza – administratively linked to INMA -, the ALBA Synchrotron and the SAI of the UNIZAR. On the part of INMA, Leyre Hernández López, David Serrate (also director of the SPM area of the LMA) and the recently incorporated researcher Mikhail M. Otrokov have also contributed to the research. Ignacio Piquero Zulaica (Technical University of Munich); Adriana Candia (Instituto de Física del Litoral, Argentina); Pierluigi Gargiani and Manuel Valvidares, scientists at the ALBA synchrotron; Fernando Delgado (University of La Laguna); Jorge Cerdá (ICMM of Madrid); and Andrés Arnau (University of the Basque Country) have also worked on the project.
Link to the publication:
Jorge Lobo-Checa, Leyre Hernández-López, Mikhail M. Otrokov, Ignacio Piquero-Zulaica, Adriana E. Candia, Pierluigi Gargiani, David Serrate, Fernando Delgado, Manuel Valvidares, Jorge Cerdá, Andrés Arnau and Fernando Bartolomé. Ferromagnetism on an atom-thick & extended 2D metal-organic coordination network. Nature Communications. DOI: 10.1038/s41467-024-46115-z.
Image:
Figure 1: Real image of the atom-thick 2D metal-organic network obtained through a tunneling microscope. / INMA-CSIC-UNIZAR
15-04-2024
