Generating magnetism in non-magnetic materials

Researchers from the Autonomous University of Barcelona (UAB) and the ICMAB have developed a wireless device that can make magnetism appear in non-magnetic materials. The emergence and control of magnetic properties in (initially non-magnetic) cobalt nitride layers using voltage, without connecting the sample to electrical wiring, could facilitate the creation of magnetic nanorobots for biomedicine and computing systems where basic information management processes do not require wiring.

Electronic devices are based on the manipulation of the electrical and magnetic properties of components, to perform computation or to store information. Controlling magnetism using voltage instead of electric currents has become an important control method to improve energy efficiency in many devices, since currents heat up circuits.

A team of researchers has now modified the magnetic properties of a thin layer of cobalt nitride (CoN) by applying electrical voltage without the use of wires. To achieve this, the researchers placed the sample of magnetic material inside a liquid with ionic conductivity and applied voltage to the liquid via two platinum plates, without connecting any wires to the sample. In this way, an induced electric field is generated that allows the nitrogen ions to leave the CoN, while causing magnetism to appear in the sample, which goes from non-magnetic to magnetic. The induced magnetic properties can be modulated as a function of applied voltage and actuation time, as well as the geometrical arrangement of the sample. Temporary or permanent changes in magnetism can also be made, depending on the orientation of the sample with respect to the imposed electric field.

Jordi Sort, an ICREA researcher at the UAB Physics Department, said achieving wireless control of the magnetism of a sample by modifying the voltage represents a paradigm shift in this area of research. “This is a finding that can have applications in very diverse fields such as biomedicine, to control the magnetic properties of nanorobots without wires, or in wireless computing, to write and erase information in magnetic memories with voltage but without wiring,” Sort said.

The methodology presented by the researchers to achieve wireless magnetic control is not exclusive to cobalt nitride. According to ICMAB researcher Nieves Casañ-Pastor, these are protocols that can be extrapolated to other materials to wirelessly control other physical properties, such as superconductivity, memory resistance control, catalysis or transitions between insulator and metal.

The research findings were published in Nature Communications.

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