The coercivity of nickel ferrite (NFO) thin films can be reduced by as much as 80% via the patterning of the surface of the material, according to new research from North Carolina State University.
This finding “opens the door” to greater energy efficiency in high-frequency electronics — such as sensors, antennas, microwave-utilizing devices, etc.
“This technique reduces coercivity, which will allow devices to operate more efficiently, reducing energy use and improving device performance,” states Goran Rasic, a PhD student at NC State and lead author of a new paper detailing the work. “We did this work on NFO but, because the reduced coercivity is a direct result of the surface patterning, we think our technique would work for other magnetic materials as well.”
The press release from North Carolina State University provides more:
Coercivity is a property of magnetized materials and is the amount of magnetic field needed to bring a material’s magnetization to zero. Basically, it’s how much a material likes being magnetic. For devices that rely on switching current back and forth repeatedly — such as most consumer electronics — you want materials that have low coercivity, which improve device performance and use less energy.
Iron oxides, like NFO, have a variety of properties that are desirable for use in high-frequency devices, but they do have a down side: they have high coercivity. The new research from NC State helps address this problem.
Through the use of an corduroy pattern imposed on the surface of NFO thin films, the coercivity can be reduced 30-80% — with the variability being dependant upon the thickness of the film. The thinner films, predictably, experience a larger reduction in coercivity.
The surface patterns used in this work were, roughly, 55 nanometers (nm) high and 750 nm wide — and ran parallel to each other, spaced about 750 nm apart.
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