Piezoelectric/electrostrictive device and method for manufacturing the same

A method for manufacturing a piezoelectric/electrostrictive device including a ZrO2 substrate, a Pt electrode layer adhering to a surface of the ZrO2 substrate, and a piezoelectric/electrostrictive layer adhering to a surface of the Pt electrode layer, the method comprising the steps of:

• a first layer forming step of forming a first layer containing Pt on a ZrO2 substrate so as to form a Pt electrode layer on a surface of the ZrO2 substrate;
• a second layer forming step of forming a second layer containing a piezoelectric/electrostrictive material comprising a solid solution of bismuth sodium titanate and potassium niobate on the first layer;
• a firing step of heating the ZrO2 substrate having the first layer and the second layer to a firing temperature to fire at least the second layer, thereby forming the piezoelectric/electrostrictive layer which has a thermal expansion coefficient that is greater than that of the ZrO2 substrate and producing the piezoelectric/electrostrictive device;
• and
• a cooling step of cooling the piezoelectric/electrostrictive device after the firing step;
• wherein the cooling step comprises a sub-step of holding the piezoelectric/electrostrictive device at a constant temperature that is lower than the firing temperature during the cooling step;
• and
• wherein the constant temperature of the cooling sub-step is within a range of temperatures at which high-temperature creep occurs in the Pt electrode layer to provide a step of deforming the Pt electrode layer by high-temperature creep during the cooling sub-step.