Researchers have developed a method that allows power conversion from DC magnetic fields to AC electric voltages using domain wall (DW) motion in ferromagnetic nanowires. The device concept relies on spinmotive force, voltage generation due to magnetization dynamics. Sinusoidal modulation of the nanowire width introduces a periodic potential for a DW, the gradient of which exerts variable pressure on the traveling DW. This results in time variation of the DW precession frequency and the associated voltage. Using a one-dimensional model, we show that the frequency and amplitude of the AC outputs can be tuned by the DC magnetic fields and wire-design.
This is a new application of spintronics is the highly efficient and direct conversion of magnetic energy to electric voltage by using magnetic nanostructures and manipulating the dynamics of magnetization.
The researchers demonstrated for the first time the feasibility of a device that generates a voltage based on manipulating an effective magnetic field within a nanowire that arises from width modulation. Technically such a field is not a true magnetic field, but it can be viewed as such. The team tested a one-dimensional model. It showed that DC magnetic field characteristics such as magnitude, and design parameters such as wire width, can be used to control, or “tune,” the frequency and amplitude of AC current. Importantly, their results showed that a variable frequency ranging from megahertz to gigahertz can be achieved. Control and range in tuning ability are highly desirable management features in generating current.
The team’s results suggest that applying their spintronics approach may one day meet a variety of commercial energy demands due to control and scalability.
SOURCES – Applied Physics Letters, Science Daily