J. Phys. IV France
Volume 137, November 2006
Page(s) 265 - 271
Publié en ligne 23 décembre 2006
35th Winter School on Wave and Quantum Acoustics
J. Bodzenta, M. Dzida and T. Pustelny
J. Phys. IV France 137 (2006) 265-271

DOI: 10.1051/jp4:2006137053

Sensing thermal conductivity and structural effects at the nanoscale by scanning thermal microscopy (SThM)

M. Chirtoc1, J. Gibkes2, J.-S. Antoniow1, J.-F. Henry1, E. Neubauer3, B. Bein2 and J. Pelzl2

1  UFR Sciences, Lab. Thermophysique UTAP/LTP, Moulin de la Housse, BP. 1039, 51687 Reims Cedex 2, France
2  Institut für Experimentalphysik, Ruhr-Universität, 44801 Bochum, Germany
3  ARC Seibersdorf Research, Dept. Materials Research, 2444 Seibersdorf, Austria

(Published online 23 December 2006)

We introduce the theoretical description of $3\omega $ signal from the Wollaston probe of a scanning thermal microscope (SThM) in terms of an equivalent low-pass filter. We performed thermal conductivity k measurements with lateral resolution of about 100 nm. The first application concerns NiTi shape memory alloys microstructured by focused ion beam implantation. Local martensite to austenite structural phase transition has been identified upon heating the sample from room temperature to 100$^{\circ}$C. The $3\omega $ signal changes were -1.95% in amplitude and 0.6$^{\circ}$ in phase, corresponding to thermal conductivity k increase of 13.5%. The second application consists of static measurement of local k on points situated on flat faces of bare diamond crystallites 300 $\mu $m in diameter, and on crystallites coated with Cr, Cu and Cu/Cr layers with thickness in the range 0.5-30 $\mu $m. The high k advantage of bare crystallites is lost upon coating the particles, but the thermal barrier depends also on the specific configuration when the particles are in contact to one another in materials obtained from such powders.

© EDP Sciences 2006