#ferromagnetism

Typically research has focused on the effects induced by different materials in graphene. Convinced that this is only half the story, Dr Zeila Zanolli turned the tables to look at the proximity effects of graphene on magnetic semiconducting substrates. Using first principles calculations she observes a switching of internal spin alignment from antiferromagnetic to ferromagnetic. Persisting close to room temperature, her findings could find applications in magnetic memories or spin filters.

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In a refreshing change of perspective, theoretical physicist Dr Zeila Zanolli has looked at the proximity effects of graphene on a magnetic semiconducting substrate, finding it to affect the substrate’s magnetism down to several layers below the surface. Her paper was published on 5 October in Physical Review B. She was also one of three recipients of the first MaX Prize for frontier research in computational materials science.

When two sheets of the carbon nanomaterial graphene are stacked together at a particular angle with respect to each other, it gives rise to some fascinating physics. For instance, when this so-called “magic-angle graphene” is cooled to near absolute zero, it suddenly becomes a superconductor, meaning it conducts electricity with zero resistance.

Now, a research team from Brown University has found a surprising new phenomenon that can arise in magic-angle graphene. In research published in the journal Science, the team showed that by inducing a phenomenon known as spin-orbit coupling, magic-angle graphene becomes a powerful ferromagnet.

“Magnetism and superconductivity are usually at opposite ends of the spectrum in condensed matter physics, and it’s rare for them to appear in the same material platform,” said Jia Li, an assistant professor of physics at Brown and senior author of the research. “Yet we’ve shown that we can create magnetism in a system that originally hosts superconductivity. This gives us a new way to study the interplay between superconductivity and magnetism, and provides exciting new possibilities for quantum science research.”

An international team of researchers, affiliated UNIST has introduced an exiting new organic network structure that shows pure organic ferromagnetic property at room temperature. As described in the CHEM journal this pure organic material exhibits ferromagnetism from pure p-TCNQ without any metal contamination.

This breakthrough has been led by by Professor Jong-Beom Baek and his research team in the School of the Energy and Chemical Engineering at UNIST. In the study, the research team has synthesized a network structure from the self polymerization of tetracyanoquinodimethane (TCNQ) monomer. The designed organic network structure generates stable neutral radicals.

For over two decades, there has been widespread scepticism around claims of organic plastic ferromagnetism, mostly due to contamination by transition metals. Extensive effort has been devoted to developing magnets in purely organic compounds based on free radicals, driven by both scientific curiosity and the potential applications of a ‘plastic magnet’. Excluding the contamination issues and realizing magnetic properties from pure organic plastics must occur to revive the quest for plastic magnetism.

Researchers at the U.S. Department of Energy’s Ames Laboratory discovered that they could functionalize magnetic materials through a thoroughly unlikely method, by adding amounts of the virtually non-magnetic element scandium to a gadolinium-germanium alloy.

It was so unlikely they called it a “counterintuitive experimental finding” in their published work on the research.

“People don’t talk much about scandium when they are talking magnetism, because there has not been much reason to,” said Yaroslav Mudryk, an Associate Scientist at Ames Laboratory. “It’s rare, expensive, and displays virtually no magnetism.”

“Conventional wisdom says if you take compound A and compound B and combine them together, most commonly you get some combination of the properties of each. In the case of the addition of scandium to gadolinium, however, we observed an abrupt anomaly.”

Years of research exploring the properties of magnetocaloric materials, relating back to the discovery of the giant magnetocaloric effect in rare earth alloys in 1997 by Vitalij Pecharsky and the late Karl Gschneidner, Jr., laid the groundwork for computational theory to begin “hunting” for hidden properties in magnetic rare-earth compounds that could be discovered by introducing small amounts of other elements, altering the electronic structure of known materials.