Stiffness Mapping TPU mechanical property AM-KPFM mechanical_property Foil MagneticPhase Mfm Nickel Magnetic bias_mode StrontiumTitanate Galfenol atomic_steps Gallium DentalProsthesis Platinum molecule Forevision SurfaceOxidation NeodymiumMagnets Indent Workfunction SiliconOxide blended polymers Lateral molecular_beam AdhesionForce electrospinning FM-KPFM Led EFMAmplitude CrAu atomic_layer