Thermal conductivities of VNx/MgO(001) (0.76≤x≤1.00) epitaxial layers, grown by reactive magnetron sputter deposition, are measured in the temperature range 300<T<1000K using time-domain thermoreflectance (TDTR). Data for the total thermal conductivity are compared to the electronic contribution to the thermal conductivity calculated from the measured electrical conductivity, the Wiedemann-Franz law, and an estimate of the temperature dependence of the Lorenz number L(T). The total thermal conductivity is dominated by electron contribution and varies between 13Wm-1K-1 at x=0.76 and 20Wm-1K-1 at x=1.00 for T=300K and between 25 and 35Wm-1K-1 for T=1000K. The lattice thermal conductivity vs x ranges from 5 to 7Wm-1K-1 at 300 K and decreases by 20% at 500 K. The low magnitude and weak temperature dependence of the lattice thermal conductivity are attributed to strong electron-phonon coupling in VN.
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy (miscellaneous)