Patent ID: 7446930

Claim:
A method of forming a domain inverted region in a ferroelectric single crystal, said method comprising; a step of forming a control layer having a larger defect density D cont1 than a defect density D ferro of said ferroelectric single crystal (D ferro <D cont1 ) in a first face perpendicular to a direction of polarization of said ferroelectric single crystal in said ferroelectric single crystal, a step of forming a first electrode on said first face, a step of forming a second electrode having a smaller area than an area of said first electrode on a second face being opposite to said first face of said ferroelectric single crystal, and a step of applying an electric field between said first electrode and said second electrode, in which a spontaneous polarization possessed by a domain inverted region generated from said second electrode is terminated through said control layer at said first electrode side, and wherein said control layer functions as physical hindrance for a growth of said domain inverted region to said first electrode by said larger defect density D cont1 .