Materials chemistry: When additives are good
Researchers have devised a simple and inexpensive approach to making soft magnetic films for microwave applications
Soft magnetic materials can be easily magnetized and demagnetized. They are widely used in microwave devices, such as absorption of electromagnetic radiations.
Developers tend to use thin films of soft magnetic materials, as opposed to their bulk form, in mobile applications, such as cell phones and laptops, as well as military applications, such as stealth aircrafts. However, the conventional approach to making soft magnetic films requires a high vacuum environment, which is expensive and time-consuming. Moreover, the usual fabrication system is not suitable for the preparation of large sheet films, thereby limiting its application in manufacturing the soft magnetic materials for microwave absorption.
Bao-Yu Zong at the A*STAR Data Storage Institute and co-workers1 have now demonstrated the viability of fabricating soft magnetic thin films through electrodeposition, a plating technique that is scalable and can be performed at room temperature. The approach is not only simpler and cheaper to operate, but also versatile enough for making a wide range of soft magnetic materials for microwave applications.
The researchers chose to work with iron–cobalt–nickel alloy, a soft magnetic material with low permeability, high coercivity and other less-than-ideal properties. They added small amounts of organic compounds, including dimethylamine borane and sodium dodecyl sulfate, to the plating solution prior to deposition. The resulting thin films had much higher permeability and lower coercivity, which make them more desirable for microwave applications. The researchers suggest that the additives might have prevented iron from oxidizing during electrodeposition, thereby improving the quality of thin films obtained.
Zong and his team also explored the effect of adding inorganic compounds, such as aluminum potassium sulfate, to the plating solution. They detected an increased resistivity in the thin films — a result that is likely to be a consequence of the change in morphology of the material; that is, the shape of the nanoparticles changed from common granular to columnar (see image), as revealed by atomic force microscopy. The iron–cobalt–nickel thin films also exhibit strong microwave absorption in comparison to ordinary magnetic films. These unique properties are perfect for high-frequency microwave applications, including magnetic data storage, portable wireless and biotechnology devices.
The researchers have high hopes that their approach is applicable to the fabrication of a wide range of soft magnetic materials. "Our technique is cost-effective and scalable. We can create soft magnetic thin films on different size and type of substrates," says Zong. "In a subsequent step, we hope to transfer this methodology to related industrial companies."
The A*STAR-affiliated researchers contributing to this research are from the A*STAR Data Storage Institute
Lee Swee Heng | Research asia research news
The most recent press releases about innovation >>>
Die letzten 5 Focus-News des innovations-reports im Überblick:
HZI researchers developed a bacterial strain that can be used in cancer therapy
Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...