BiFeO3 HumanHair FM_SKPM Typhimurium ring shape AM_KPFM PyroelectricDetector Chemical_Vapor_Deposition Topography flakes Tin sulfide Lanthanum_aluminate membrane VerticalPFM STM food Defect hetero_structure DeoxyribonucleicAcid PDMS UnivOfMaryland SetpointMode Hysteresys Alloy NeodymiumMagnets MultiferroicMaterials PinpointPFM CrAu ThinFilm Vortex Liquid Annealing NUSNNI Boundary Magnetic Force Microscopy