Facilities

Objectifs

  • Measurement of behaviors and construction of experimental databases,

  • Study of response mechanisms to certain solicitations, relevant scale,

  • Identification of intrinsic properties, of model behavior parameters.

Outline

The coupled properties of thin films are essential for MEMS applications (or for micro-actuators) and for sensors because they permit the access to physical quantity through another one. For instance, piezoelectric materials are bent under the action of electrical field and, inversely, they are electrically polarized under the action of mechanical stress. On the other hand, a concrete explanation of materials and surfaces properties needs a good knowledge of mechanisms and of physical phenomena that occur at different scales. In consequence, the characterization under different physical solicitations but simultaneous (and/or multi-physic) of thin films, interfaces and surfaces behaviors at different scales is an important activity of this group. The investigations concern principally the properties of electrical conductivity, of phase changes at solid state under various solicitations, of tribology, of surface forces or also adhesion. The characterization scale goes from nanometers to few millimeters for the global behavior of thin films. These characterizations implement conventional means but also they need the development of specific experimental tools for multiphysic characterization (ex or in situ) built up in collaboration with other groups in FEMTO. The main motivations of this theme are to enable: to establish a relation between properties and elaboration processes, a better understanding of elementary mechanisms present at different scales leading to the observed macroscopic behavior. The multiphysic properties currently studied are: the magneto-mechanical behavior of ferromagnetic shape memory alloy thin films of type Ni-Mn-Ga, the mechanical stresses that are often severe in thin films on substrate, the electrical conduction properties in GLAD chromium-based films, the influence of different physical and physico-chemical parameters intense in the macroscopic friction via the formation and the agglomeration of wearing nanoparticules, the structural characteristics (optical and electronic) of metallic oxynitrure with variable compositions.

Key words

Multiphysics, multiscales, characterizations, Shape Memory Alloy (SMA), tribofilms, ferromagnetism.

Characterization techniques

  • The classical ones into the group: µDSC, multi-scale (nano - macro) tribometer, electro-magnet, spectroscopy in reflexion and in transmission (180-3000 nm),

  • In collaboration: SEM, AFM, SThM, XRD, nano-indenter, micro et nano-scratch, …

  • The multiphysic specific ones developed in the group:

    - Measurement of electrical resistivity, mobility and concentration in carrier as a function of temperature in the range 90-600 K,
    - Measurement of strain as a function of magnetic field until 1 T via the deflexion measurement of micro-beam.

Collaborations

Universities of Dijon, Lisbon, Minho, Mulhouse, Namur, EPFL, National network of great clean rooms (RTB in French), …