Material integration promises next generation smart devices

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Researchers from North Carolina State University have integrated bismuth ferrite (BFO) as a single crystal onto a silicon chip, an advance that could lead to a new generation of multifunctional, smart devices.

BFO can be magnetised by running an electric current through the material and potential applications for it include new magnetic memory devices, smart sensors and spintronics technologies.

According to NCSU, integrating the BFO into the silicon substrate as a single crystal makes the BFO more efficient by limiting the amount of electric charge that ‘leaks’ out of the BFO into the substrate.

‘This work means we can now look at developing smart devices that can sense, manipulate and respond to data more quickly because it all happens on one chip – the data doesn’t need to be relayed elsewhere,’ said Dr Jay Narayan, John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and senior author of a paper describing the work.

The researchers also found that they can switch the polarity of the BFO’s magnetic field with as little as four volts, which is comparable to the voltage needed in existing integrated circuits. This is a key to developing functional technologies because higher voltages and fields are impractical and use more energy, which could damage and disrupt electronic functions.

Similarly, the researchers found that a low-strength, external magnetic field – measured at 300 Oersted – can also switch the BFO’s polarity. This is significant because external magnetic fields don’t generate heat in the BFO, which could be important for some applications.

The research is detailed in Nano Letters.