LAUSR

Abstract The figure of merit for energy harvesting of a thermomagnetic oscillator has been analyzed. For the first time, a figure of merit for a thermomagnetic device combining the material properties and device parameters has been established. Our analysis indicates that alloys with a sharp magnetic transition with respect to temperature and lower hysteresis exhibit higher figure of merit for a given set of heat load and heat sink temperatures. The material with the highest figure of merit, (MnNiSi)0.68(Fe2Ge)0.32, was employed to construct a thermomagnetic oscillator. A thermomagnetic alloy was coupled to a permanent magnet by a flexible spacer, one end of the flexible spacer was attached to the thermomagnetic alloy and the other to the permanent magnet. Use of a flexible spacer increases the oscillation frequency by 32% compared to a rigid spacer. The permanent magnet also exhibited damped oscillations, resulting in an increase voltage/cycle by 18% compared to the rigid spacer case. Thus, figure of merit is a suitable guideline for tuning the material properties and optimizing the device parameters for maximizing the performance of the thermomagnetic oscillator.