Ni-FeAlloy kelvin probe force microscopy Inorganic_Compound frequency_modulation VerticalPFM Hair FFM Bmp Holes EPFL Chloroform TemperatureControlledAFM NtuEee UnivOfMaryland Graphene MESA structure PinPointMode Calcite StainlessSteel DeoxyribonucleicAcid PVAC Defect MechanicalProperty Electrode Metal Ram ItoGlass FrictionForce Platinum nanobar ScanningSpreadingResistanceMicroscopy Optoelectonics amplitude_modulation Hysteresys Growing