Multi-field nanoindentation apparatus for measuring local mechanical properties of materials in external magnetic and electric fields

摘要

Nano/micro-scale mechanical properties of multiferroic materials can becontrolled by the external magnetic or electric field due to the couplinginteraction. For the first time, a modularized multi-field nanoindentationapparatus for carrying out testing on materials in externalmagnetostatic/electrostatic field is constructed. Technical issues, such as theapplication of magnetic/electric field and the processes to diminish theinterference between external fields and the other parts of the apparatus, areaddressed. Tests on calibration specimen indicate the feasibility of theapparatus. The load-displacement curves of ferromagnetic, ferroelectric andmagnetoelectric materials in the presence/absence of external fields reveal thesmall-scale magnetomechanical and electromechanical coupling, showing as theDelta-E and Delta-H effects, i.e. the magnetic/electric field induced changesin the apparent elastic modulus and indentation hardness.