UCLA researchers in the Department of Mechanical and Aerospace Engineering have developed an energy radiator based on a spin torque nano-oscillator that does not require the application of an external field.
Energy radiators are ubiquitous in most modern electronics involving receiving or emitting oscillations, state change detection, and timing. Common products include DC to AC converters, antennas, magnetic field sensors, precision timing systems, and magnetic recording heads in hard drives. The ability to control the oscillations is achieved by spin-transfer torque. Spin-transfer torque is the process of changing a magnet's polarization by transferring current from another magnet through either a high- or low-resistance barrier. Achieving this effect generally requires the application of an external magnetic field, which is an energy sink. Several designs have been proposed to eliminate the external field issue. However, those methods require complex fabrication processes and lack tunability. Designs providing tunability, simple fabrication, and the ability to operate the device without an external field would make radiators more energy efficient and desirable for energy-limited and on-chip applications.
UCLA researchers have developed a spin torque nano-oscillator that is more efficient and practical than previous spin transfer torque-based oscillators. This is achieved by using a hybrid system of strain and spin-orbit torque. The array design allows for two controllable inputs (current and strain) which affect the output frequency and amplitude. This invention eliminates the need for an external applied field, utilizes a simplified fabrication process, and provides a high level of tunability.
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