In-situwhite-beamsynchrotronradiationtopographicobservationsunderanelectricfieldhavebeenmadeonKTiOPO4familycrystals.Theinvestigationshowsastrongenhancementofdiffractedintensityofhklreflections(l≠0)andthetopographicextinctioncontrast,whenthefieldisappliedalongthepolaraxis.Dopedandundopedsampleswithgrown-indefectsarestudiedindetail.ItisbelievedthatthemovementofK^+ionsdrivenbythefieldleadstoalocalaccumulationofchargesandthelatticedistortion.Allthefield-relatedphenomenaappeartoberelatedtotheone-dimensionalionicconductance.
