Temperature measurement based on the magneto-optic Kerr effect in Ni nanofilms

Thermometry is essential in laboratory and industry settings. We propose a noninvasive temperature measurement method based on the superparamagnetic properties of nickel-plated films. When the nickel (Ni) film is uniformly heated from 100 K to 300 K, we observe that the polarization angle of the reflected polarized light decreases correspondingly. Compared with optical temperature measurement, this method introduces magnetic physical quantity, which increases the penetration of temperature measurement. Compared with magnetic temperature measurement, this method introduces optical physical quantity, which greatly increases the amount of information contained in the measurement channel. On this basis, we introduce the characteristic matrix of membrane system, and the improved the mean field theory which can interpret superparamagnetism. Our experiment has demonstrated that the above theoretical model is feasible from low temperature to normal temperature. The thin film sensor element provides the necessary temperature information for cryogenic wind tunnel design and hypersonic vehicle surface model design in real time