A method for producing a piezoelectric single crystal ingot shows small variation in the concentration of PbTiO.sub.3 in the growth direction of single crystal. A complete solid solution-type piezoelectric single crystal ingot is produced by using the Bridgman method, including: filling a starting material, wherein a relaxor having a compositional formula Pb(B.sub.1, B.sub.2)O.sub.3 is blended with lead titanate having a composition PbTiO.sub.3 to give a preset composition, into a crucible for growth; heating to the melting temperature to give a melted liquid layer; then moving the crucible for growth toward the low temperature side; and thus starting one-direction solidification from the lower part of the crucible to thereby produce a single crystal. During solidification, the feedstock containing the relaxor and lead titanate having a maximum grain size ≤3 mm is continuously supplied into the crucible.

To provide a lithium niobate (LN) substrate which allows treatment conditions regarding a temperature, a time, and the like to be easily managed and in which an in-plane distribution of a volume resistance value is very small, and a method of producing the same. A method of producing an LN substrate by using an LN single crystal grown by the Czochralski process, in which an LN single crystal having a Fe concentration of more than 1000 mass ppm and 2000 mass ppm or less in the single crystal and processed into a form of a substrate is buried in an Al powder or a mixed powder of Al and Al.sub.2O.sub.3, and heat-treated at a temperature of 550 C. or more and 600 C. or less, to produce a lithium niobate single crystal substrate having a volume resistivity controlled to be within a range of 110.sup.8 .Math.cm or more to 110.sup.10 .Math.cm or less.

A piezoelectric material for a combustion pressure sensor, a method for producing the piezoelectric material, and a combustion pressure sensor using the piezoelectric material are provided. The piezoelectric material of the present invention includes a single crystal containing Ca, Ta, an element M (M is Al or Ga), Si, and O, the single crystal has the same crystal structure as the crystal structure of langasite represented by La.sub.3Ga.sub.5SiO.sub.14, and at least the content of the element M is insufficient for the stoichiometric composition represented by Ca.sub.3TaM.sub.3Si.sub.2O.sub.14. Preferably, in a case where the element M is Ga, each content of the Ca and the Si is excessive for the stoichiometric composition, and in a case where the element M is Al, the content of the Ca is excessive for the stoichiometric composition, and the content of the Ta is insufficient for the stoichiometric composition.

Provided is a surface acoustic wave device using a novel and steadily suppliable piezoelectric material that is resistant to a high-temperature environment and enables the surface acoustic wave device to use a 2 GHz to 2.5 GHz band or higher. The surface acoustic wave device includes: a piezoelectric substrate formed from a monocrystal of gehlenite (CAS: Ca2Al(AlSi)O7); and interdigital transducers formed on a surface acoustic wave propagation plane of the piezoelectric substrate.

To provide a method of producing a lithium niobate (LN) substrate which allows treatment conditions regarding a temperature, a time, and the like to be easily managed and in which an in-plane distribution of a volume resistance value is very small, and also variations in volume resistivity are small among substrates machined from the same ingot. A method of producing an LN substrate by using an LN single crystal grown by the Czochralski process, in which a lithium niobate single crystal having a Fe concentration of 50 mass ppm or more and 2000 mass ppm or less in the single crystal and being in a form of an ingot is buried in an Al powder or a mixed powder of Al and Al.sub.2O.sub.3, and heat-treated at a temperature of 450 C. or more and less than 660 C., which is a melting point of aluminum, to produce a lithium niobate single crystal substrate having a volume resistivity controlled to be within a range of 110.sup.8 .Math.cm or more to 210.sup.12 .Math.cm or less.

A method for producing a piezoelectric single crystal ingot shows small variation in the concentration of PbTiO.sub.3 in the growth direction of single crystal. A complete solid solution-type piezoelectric single crystal ingot is produced by using the Bridgman method, including: filling a starting material, wherein a relaxor having a compositional formula Pb(B.sub.1,B.sub.2)O.sub.3 is blended with lead titanate having a composition PbTiO.sub.3 to give a preset composition, into a crucible for growth; heating to the melting temperature to give a melted liquid layer; then moving the crucible for growth toward the low temperature side; and thus starting one-direction solidification from the lower part of the crucible to thereby produce a single crystal. During solidification, the feedstock containing the relaxor and lead titanate having a maximum grain size 3 mm is continuously supplied into the crucible.

The present disclosure relates generally to processes for preparing metal oxide nanosheets. In particular, the process may comprise generating a liquid metal film comprising a metal oxide surface layer, and exfoliating the metal oxide surface layer to form a metal oxide nanosheet. The present disclosure also relates generally to devices comprising the metal oxide nanosheets, such as piezoelectric generators and sensors.

The present disclosure relates generally to processes for preparing metal oxide nanosheets. In particular, the process may comprise generating a liquid metal film comprising a metal oxide surface layer, and exfoliating the metal oxide surface layer to form a metal oxide nanosheet. The present disclosure also relates generally to devices comprising the metal oxide nanosheets, such as piezoelectric generators and sensors.

A method for producing a piezoelectric film includes forming a metal film, recrystallizing a portion of the metal film by heating, forming an amorphous film of piezoelectric material on the metal film; and heating the amorphous film at a position of the recrystallized portion of the metal film.

The present invention makes clear and defines a congruent composition of a langasite-based oxide, and establishes a method of manufacturing a crystal by any desired composition of AE.sub.3ME.sub.1+a(Ga.sub.1-xAl.sub.x).sub.3+bSi.sub.2+cO.sub.14 (AE is an alkaline-earth metal, ME is Nb or Ta, 0x1, 0.5<a0 or 0<a<0.5, 0.5<b0 or 0<b0.5, and 0.5<c0 or 0<c<0.5, excluding a=b=c=0). This makes it possible to suppress the formation of an impurity, and improve the yield and crystal manufacturing rate. The raw material is a raw material mixture prepared by mixing an alkaline-earth metal or its carbonate or oxide, Nb or Ta or its oxide, Ga or its oxide, Al or its oxide, and Si or its oxide.