D. R. Birt, An, K. M., Weathers, A., Shi, L., Tsoi, M., and Li, X. Q., “"Brillouin Light Scattering Spectra as Local Temperature Sensors for Thermal Magnons and Acoustic Phonons,” Appl. Phys. Lett., vol. 102, pp. 082401, 2013.
We demonstrate the use of the micro-Brillouin light scattering (micro-BLS) technique as a local temperature sensor for magnons in a permalloy (Py) thin film and phonons in the glass substrate. When the Py film is uniformly heated, we observe a systematic shift in the frequencies of two thermally excited perpendicular standing spin wave modes. Fitting the temperature dependent magnon spectra allows us to achieve a temperature resolution better than 2.5 K. In addition, we demonstrate that the micro-BLS spectra can be used to measure the local temperature of magnons and the relative temperature shift of phonons across a thermal gradient. Such local temperature sensors are useful for investigating spin caloritronic and thermal transport phenomena in general.