Thermal conductivities and phase transition temperatures of various phase-change materials measured by the 3ω method

We have employed the " 3ω method" to determine the thermal conductivities of the amorphous and crystalline phases of the technologically important materials Ge2 Sb2 Te5, nitrogen-doped Ge2 Sb2 Te5, Ag- and In-doped Sb2 Te, and Ge15 Sb85. We used the " 3ω voltage" as a monitor of thermal conductivity that allowed us to observe the amorphous-to-crystalline phase transition as the material was annealed. For these materials, our results reveal that the thermal conductivity κ is related to the electrical conductivity σ by an empirical relationship of the form κ=σLT+0.175 W/m K, where L is the Lorenz number and T is temperature. © 2009 American Institute of Physics.