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A New Material For Wearable Spintronic Devices

Researchers have made a bendable, stretchable multiferroic film

1 min read
A New Material For Wearable Spintronic Devices
Image: YoungPak Lee/ Hanyang University

Researchers in South Korea have taken a step towards wearable devices based on spintronics. They have made a stretchy thin film that retains its useful electric and magnetic properties even when highly curved.

While conventional electronic circuits exploit an electron’s charge-carrying property, spintronics harnesses the quantum mechanical property of electrons known as spin. The premise is that you can flip electrons’ spin by applying a small voltage in special multiferroic materials.

Researchers are trying to use this property to create special kinds of magnetic logic circuits and non-volatile magnetic memories that would be denser, faster, and more energy-efficient than today’s technology. That means smartphones and computers that switch on instantly and consume a fraction of the energy they do today.

The South Korean team used the promising multiferroic material bismuth ferrite. While many known multiferroics require low temperatures to work, bismuth ferrite works at room temperatures. The problem with devices made from the material though is their high leakage current, “which hinders the strong electric properties," said YoungPak Lee, a physics professor at Hanyang University in Seoul, said in a press release.

Lee and his colleagues found that making a flexible film from bismuth ferrite improved the material’s electric and magnetic properties. They started by making bismuth ferrite nanoparticles that were about 24nm in size. They mixed these in a polymer solution and dried it to make a flexible, slightly stretchable film. The thin film kept its improved electric and magnetic properties even when bent into a cylinder.

The small size of the nanoparticles improve the materials’ magnetic properties while the polymer’s dielectric properties improved the current-leakage problem, the researchers say. Lee and his coworkers reported their results in Applied Physics Letters.

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The Transistor at 75

The past, present, and future of the modern world’s most important invention

2 min read
A photo of a birthday cake with 75 written on it.
Lisa Sheehan
LightGreen

Seventy-five years is a long time. It’s so long that most of us don’t remember a time before the transistor, and long enough for many engineers to have devoted entire careers to its use and development. In honor of this most important of technological achievements, this issue’s package of articles explores the transistor’s historical journey and potential future.

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