BismuthFerrite KPFM conductive Vortex PatternedSapphireSubstrat MESA structure PtfeMembrane Dr.JurekSadowski Chrome frequency_modulation GaP YttriaStabilizedZirconia ring shape HfO2 I-VSpectroscopy ThinFilm PrCurve LowDensityPolyethylene blended polymers SrTiO3 OrganicSemiconductor Self-assembledMonolayer UnivOfMaryland MultiferroicMaterials PDMS FAFailureAnlaysis Multiferroic_materials Water molecular_self_assembly Transparent FrictionForce SiliconCrystal Sperm tip_bias_mode pulsed_laser_deposition