The physical properties of nanomaterials: A challenge in materials science

In this work, some initial efforts to determine the physical properties of metallic films with thickness values below 200 nm are described. The proposed methodologies to measure the temperature coefficient of resistance, the specific heat, thermal diffusivity, thermal conductivity values of Au, Al, and Cu films as such as the elastic modulus of metallic nano-alloys are discussed. The thermal properties were obtained from the metallic films deposited from 20 to 200 nm-thickness on glass substrates, which are heated with an electrical pulse during some microseconds. The rate of heating captured during this short time permits to estimate the thermal properties of exclusively the metallic film without affectation of the substrate. On the other hand, the elastic module of metallic thin films, estimated by subtracting the effect of the previously characterized polymeric substrates, was obtained from the stress-strain curves. Obtained values for the thermal and mechanical properties show a decrease or increase behavior with the thickness value, very different than for their corresponding bulk values.