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Category: materials – Page 74

Directing magnetization with a low electric field is crucial for advancing effective spintronic devices. In spintronics, the characteristics of an electron’s spin or magnetic moment are leveraged for information storage. By modifying orbital magnetic moments through strain, it’s possible to manipulate electron spins, leading to an enhanced magnetoelectric effect for superior performance.

Japanese researchers, including Jun Okabayashi from the University of Tokyo, revealed a strain-induced orbital control mechanism in interfacial multiferroics. In multiferroic material, the magnetic property can be controlled using an electric field—potentially leading to efficient spintronic devices. The interfacial multiferroics that Okabayashi and his colleagues studied consist of a junction between a ferromagnetic material and a piezoelectric material. The direction of magnetization in the material could be controlled by applying voltage.

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Electronics are based on electrical charges being transported from one place to another. Electrons move, current flows, and signals are transmitted by applying an electrical voltage. However, there is also another way to manipulate electronic currents and signals: using the properties of the spin—the intrinsic magnetic moment of the electron. This is called “spintronics,” and it has become an increasingly important field in contemporary electronic research.

An international research team involving TU Wien and the Czech Academy of Sciences has now achieved an important breakthrough. They have managed to switch the spins in an antiferromagnetic material using surface strain. This could lead to an important new line of research in electronic technologies. The research is published in the journal Advanced Functional Materials.

“There are different types of magnetism,” explains Sergii Khmelevskyi from the Vienna Scientific Cluster Research Center, TU Wien. “The best known is ferromagnetism. It occurs when the atomic spins in a material are all aligned in parallel. But there is also the opposite, antiferromagnetism. In an antiferromagnetic material, neighboring atoms always have opposite spins.” Their effects therefore cancel each other out and no can be detected from the outside.

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A multi-institutional team of Chinese engineers has developed a proof-of-concept calcium-based battery that withstands 700 charge cycles at room temperature. In their paper published in the journal Nature, the group describes the challenges they addressed in developing the battery and what they have learned about the possible use of calcium-based batteries in consumer products in the future.

The current standard for rechargeable batteries used in consumer products is lithium. But because it is a rare material and has issues such as poor aging and the need to prevent overcharge, scientists have been looking for a suitable replacement. One such material is calcium, which is 2,500 times as abundant as lithium.

Prior research has suggested based on calcium should be possible if problems can be resolved. One of the biggest challenges is finding suitable electrolyte and electrode materials that can provide stability and safety.

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There is now a new addition to the magnetic family: thanks to experiments at the Swiss Light Source SLS, researchers have proved the existence of altermagnetism. The experimental discovery of this new branch of magnetism is reported in Nature and signifies new fundamental physics, with major implications for spintronics.

Magnetism is a lot more than just things that stick to the fridge. This understanding came with the discovery of antiferromagnets nearly a century ago. Since then, the family of magnetic materials has been divided into two fundamental phases: the ferromagnetic branch known for several millennia and the antiferromagnetic branch.

The experimental proof of a third branch of magnetism, termed altermagnetism, was made at the Swiss Light Source SLS, by an international collaboration led by the Czech Academy of Sciences together with Paul Scherrer Institute PSI.

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The lunar sample returned by China’s 2020 lunar mission contained minerals that provide clues to their origin. China’s Chang’e-5, the first lunar sample return mission since the Soviet Union’s Luna 24 in 1976, delivered 1.73 kilograms of regolith from the Oceanus Procellarum, a plane named for its vast size. The sample landed with CE-5 in late 2020 and included a new mineral, Changesite-(Y), as well as a perplexing combination of silica minerals. Researchers now compare CE-5’s material composition to other lunar and Martian regolith samples and examine potential causes and origins for the lunar sample’s unique makeup.

Earth’s moon achieved its Swiss cheese appearance from celestial objects crashing into its surface, forming impact craters. But craters weren’t all that was left behind; the intense pressure and temperature of such a collision also impacts the rocks and dust covering the lunar surface, known as regolith, altering its mineral composition and structure. Analyzing the resulting minerals provides modern researchers clues to the moon’s past.

China’s Chang’e-5, the first lunar sample return mission since the Soviet Union’s Luna 24 in 1976, delivered 1.73 kilograms of regolith from the Oceanus Procellarum, a plane named for its vast size.

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Year 2023 😗 😁

A new study published in the Journal of Hazardous Materials by researchers at the Royal Botanic Gardens, Kew, and partners has identified a diverse microbiome of plastic-degrading fungi and bacteria in the coastal salt marshes of Jiangsu, China.

The international team of scientists counted a total of 184 fungal and 55 bacterial strains capable of breaking down polycaprolactone (PCL), a biodegradable polyester commonly used in the production of various polyurethanes. Of these, bacterial strains within the genera Jonesia and Streptomyces have the potential to further degrade other petroleum-based polymers—natural or synthetic chains of molecules bound together.

The plastic-degrading microorganisms were sampled in May 2021 from Dafeng in eastern China, a UNESCO-protected site near the Yellow Sea Coast. The sampling confirmed the presence of a terrestrial plastisphere, a term that is relatively new to terrestrial ecology as past studies have primarily focused on marine environments. The microbiome of this “man-made ecological niche” of coastal plastic debris was further found to be distinct from the surrounding soil.

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Researchers have demonstrated that magnetic spin waves called magnons can be controlled by voltage and thus could operate more efficiently as information carriers in future devices.

Magnonic devices are being developed to transmit signals, not with electrons, but with magnons—traveling waves in the magnetic ordering of a material. New work provides one of the missing elements of the magnonics toolbox: a voltage-controlled magnon transistor [1]. The device is made up of a magnetic insulator sandwiched between two metal plates. The researchers show that they can control the flow of magnons in the insulator through voltages applied to the plates. The results could lead to more-efficient magnonic devices.

A magnon can be imagined as a row of fixed magnetic elements, or “spins,” that tilt and rotate their orientations in a coordinated pattern. This “spin wave” can carry information through a material without involving the movement of charges, which can cause undesirable heating in a circuit. Magnonics—though still in its infancy—is a potentially energy-efficient alternative to traditional electronics, says Xiu-Feng Han from the Chinese Academy of Sciences. The challenge right now for the magnonics field, he says, is developing practical versions of the four basic components of a magnonic circuit: a generator, a detector, a switch, and a transistor.

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