Nanoscale heat transport studied by high-resolution time-resolved x-ray diffraction

作者：Shayduk Roman; Navirian Hengameh; Leitenberger Wolfram; Goldshteyn Jevgenij; Vrejoiu Ionela; Weinelt Martin; Gaal Peter; Herzog Marc; Schmising Clemens von Korff; Bargheer Matias^*

来源：New Journal of Physics, 2011, 13(9): 093032.

DOI：10.1088/1367-2630/13/9/093032

We report on synchrotron-based high-repetition rate ultrafast x-ray diffraction (UXRD) experiments monitoring the transport of heat from an epitaxial La(0.7)Sr(0.3)MnO(3)/SrTiO(3) superlattice (SL) into the substrate on timescales from 100 ps to 4 mu s. Transient thermal lattice expansion was determined with an accuracy of 10(-7), corresponding to a sensitivity to temperature changes down to 0.01 K. We follow the heat flow within the SL and into the substrate after the impulsive laser heating leads to a small temperature rise of Delta T = 6 K. The transient lattice temperature can be simulated very well using the bulk heat conductivities. This contradicts the interpretation of previous UXRD measurements, which predicted a long-lasting expansion of SrRuO(3) for more than 200 ps. The disagreement could be resolved by assuming that the heat conductivity changes in the first hundred picoseconds.

• 出版日期2011-9-20