We report a hybrid particle filter for measurement of specific heat, cp, and thermal conductivity, κ, of a micro- or nanowire using the well-known 3ω method. In the 3ω method, current at frequency ω is passed through the sample, and the 3ω component of the voltage response is measured. The data analysis approach used by previous authors neglects time-varying and higher-order terms in a series expansion of the 1D transient heat equation. This approximation is inaccurate at high currents and high frequencies. We remove this source of estimation error with a transient electrothermal finite element model. A Kalman filter estimates the temperature distribution in the wire, while a particle filter estimates κ and cp. Experiments on a ∼ 30 μm diameter platinum wire confirm that current and frequency sensitivity are reduced using our approach. Furthermore, our method is applicable to compensation of other geometric and material effects that cannot be handled by the previous formulation.

This content is only available via PDF.
You do not currently have access to this content.