Anisotropic Resistivity Size Effect in Epitaxial Mo(001) and Mo(011) Layers.

Mo(001) and Mo(011) layers with thickness = 4-400 nm are sputter-deposited onto MgO(001) and α-AlO(112¯0) substrates and their resistivity is measured in situ and ex situ at room temperature and 77 K in order to quantify the resistivity size effect. Both Mo(001) and Mo(011) layers are epitaxial single crystals and exhibit a resistivity increase with decreasing due to electron surface scattering that is well described by the classical Fuchs and Sondheimer model. Data fitting yields room temperature effective electron mean free paths 14.

Depinning Dynamics of Crack Fronts.

We investigate experimentally and theoretically the dynamics of a crack front during the microinstabilities taking place in heterogeneous materials between two successive equilibrium positions. We focus specifically on the spatiotemporal evolution of the front, as it relaxes to a straight configuration, after depinning from a single obstacle of controlled strength and size. We show that this depinning dynamics is not controlled by inertia, but instead by the rate dependency of the dissipative mechanisms taking place within the fracture process zone.