Polar nanoregions engineered relaxor-PbTiO3 ferroelectric crystals

A method for forming a relaxor-PT based piezoelectric crystal, comprising:

• pre-synthesizing precursor materials by calcining mixed oxides at a first calcination temperature;
• mixing the precursor materials with single oxides and calcining at a second calcination temperature lower than the first calcination temperature to form a feeding material having the general formula of (Pb1-1.5xMx){[(MI,MII)1-z(MI′,MII′)z]1-yTiy}O3;
• and
• growing the relaxor-PT based piezoelectric crystal having the general formula of (Pb1-1.5xMx){[(MI,MII)1-z(MI′,MII′)z]1-yTiy}O3 from the feeding material by a Bridgman method,
• wherein:
• M is a rare earth cation selected from the group consisting of Nd3+, Pm3+, Sm3+, Gd3+, and combinations thereof;
• MI is selected from the group consisting of Mg2+, Zn2+, Yb3+, Sc3+, and In3+;
• MII is Nb5+;
• MI′ is selected from the group consisting of Mg2+, Yb2+, Sc3+, In3+, and Zr4+;
• MII′ is Nb5+ or Zr4+;
• 0<x≤0.05;
• 0.02<y<0.7;
• and
• 0≤z<1,
• provided that if either MI′ or MII′ is Zr4+, both MI′ and MII′ are Zr4+, and
• provided that if M is Nd3+, 0<x<0.02,
• wherein the relaxor-PT based piezoelectric crystal is a single crystal boule, and
• wherein the relaxor-PT based piezoelectric crystal, relative to a comparative crystal having a comparative formula of Pb{[(MI,MII)1-z(MI′,MII′)z]1-yTiy}O3 with the same selections and values for y, z, MI, MII, MI′, and MII′ and the same crystal symmetry after poling, has at least one of:
• less variation of dielectric permittivity and piezoelectric coefficient, along a rhombohedral phase section;
• higher piezoelectric coefficient;
• higher free dielectric permittivity;
• higher clamped dielectric permittivity;
• or
• combinations thereof.

A relaxor-PT based piezoelectric crystal comprising the general formula of (Pb1-1.5xMx){[(MI,MII)1-z(MI′,MII′)z]1-yTiy}O3,

• wherein:
• M is a rare earth cation other than La3+;
• MI is selected from the group consisting of Mg2+, Zn2+, Yb3+, Sc3+, and In3+;
• MII is Nb5+;
• MI′ is selected from the group consisting of Mg2+, Zn2+, Yb3+, Sc3+, In3+, and Zr4+;
• MII′ is Nb5+ or Zr4+;
• 0<x≤0.05;
• 0.02<y<0.7;
• and
• 0≤z<1,
• provided that if either MI′ or MII′ is Zr4+, both MI′ and MII′ are Zr4+,
• provided that if M is Nd3+, 0<x<0.02,
• provided that if z is 0, M is selected from the group consisting of Ce3+, Pr3+, Nd3+, Pm3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+, and combinations thereof, and
• provided that if 0<z<1, M is selected from the group consisting of Ce3+, Pr3+, Nd3+, Pm3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Lu3+, and combinations thereof, and
• wherein the relaxor-PT based piezoelectric crystal is a single crystal boule.