Regensburg 2022 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MM: Fachverband Metall- und Materialphysik

MM 21: Transport in Materials: Thermal transport

MM 21.3: Vortrag

Mittwoch, 7. September 2022, 10:45–11:00, H45

A spatially resolved optical method to measure thermal diffusivity — •Fei Sun¹, Simli Mishra¹, Philippa H McGuinness¹, Zuzanna h Filipiak¹, Igor Markovic¹, Dmitry A Sokolov¹, Naoki Kikugawa², Joseph W Orenstein^3,4, Sean A Hartnoll⁵, Andrew P Mackenzie^1,6, and Veronika Sunko^1,3 — ¹Max Planck Institute, CPfS, Dresden, Germany — ²NIMS, Ibaraki, Japan — ³UC Berkeley, California, USA — ⁴LBNL, California, USA — ⁵Univ. of Cambridge, Cambridge, UK — ⁶Univ. of St Andrews, St Andrews, UK

We introduce an optical method to directly measure thermal diffusivity across a broad range of temperatures. Two laser beams are used, one as a source to locally modulate the temperature, and the other as a probe of the reflectivity. Thermal diffusivity is obtained from the phase delay between two beams. Combining the technique with a microscope setup allows for spatially resolved measurements. The in-plane diffusivity can be obtained when overlapping the two laser beams instead of separating them in the traditional way, which further enhances the spatial resolution. We demonstrate on two ruthernates: Sr₃Ru₂O₇ and Ca₃Ru₂O₇. The spatial resolution allowed us to study the diffusivity in single domains of the latter, and we uncovered a temperature-dependent in-plane diffusivity anisotropy. Finally, we used the enhanced spatial resolution to study the Ti-doped Ca₃Ru₂O₇. We observed large variations of transition temperature over the same sample, originating from doping inhomogeneity, and pointing to the power of spatially resolved techniques in accessing inherent properties.