Patent ID: 7303828

Claim:
A ferroelectric film including a perovskite ferroelectric or a bismuth layer-structured ferroelectric shown by ABO 3 or (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2− (wherein A represents at least one ion selected from the group consisting of Li + , Na + , K + , Pb 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Bi 3+ and La 3+ , B represents at least one ion selected from the group consisting of Fe 3+ , Ti 4+ , Zr 4+ , Nb 5+ , Ta 5+ , W 6+ and Mo 6+ , and m is a natural number), wherein at least four-fold coordinated Si 4+ or Ge 4+ is included in the A site ion.