Piezoelectric Crystal

Introduction:
Gallium lanthanum silicate (La3Ga5SiO14, abbreviated as LGS) crystal is a multifunctional crystal material with excellent comprehensive properties. Compared to quartz crystals, LGS crystals have higher electromechanical coupling coefficients and piezoelectric constants, which are 2-3 times that of quartz crystals; Has lower sound attenuation than quartz crystals; It also has a zero temperature coefficient tangent shape; Can be used to manufacture surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices; It has no phase transition from room temperature to melting point temperature (1470 ºC) and has great potential for application in wide bandwidth piezoelectric devices and high-temperature sensors; In addition, LGS crystals also have high dielectric constant and elastic coefficient, which can be used to manufacture electro-optic Q-switching devices.
Gallium lanthanum tantalate crystals (La3Ga5.5Ta0.5O14, LGT) and gallium lanthanum niobate crystals (La3Ga5.5Nb0.5O14, LGN) are isomorphic crystals of LGS crystals, both of which have piezoelectric properties similar to those of LGS crystals. The high-temperature resistivity of LGT crystals is higher than that of LGS crystals, indicating better high-temperature performance.
Gallium lanthanum silicate isomorphic crystals belong to a uniform melt and are prone to growing large-sized crystals. At present, they can stably grow large-sized crystals with a diameter of 75mm and a length of over 150mm in batches, with excellent quality.




Features:

High electromechanical coupling coefficient;

High piezoelectric coefficient;

Having zero temperature cutting;

No phase transition;

Large scale growth;

Application:

Surface acoustic wave (SAW) resonators and filters;

Body acoustic wave (BAW) resonator;

High temperature sensor;

Electro optic Q-switch;




Physical and chemical properties:

Chemical formula La3Ga5SiO14 (LGS) La3Ga5.5Ta0.5O14 (LGT) La3Ga5.5Nb0.5O14 (LGN)

Crystal structure tripartite tripartite tripartite

Lattice parameters a=8.172 Å, c=5.102 Å a=8.231 Å, c=5.129 Å a=8.234 Å, c=5.125 Å

Density 5.75 g/cm3 5.905 6.145

Melting point 1470 ° C 1470 ° C 1470 ° C

Specific heat capacity/(J/g · K) 0.47 0.38 0.5

Hardness (Mohs) 5.5 5.5 5.5 5.5

Refractive index @ 632nm no=1.8996, ne=1.9111 no=1.9388 no=1.9497

Dielectric constant ε 11=19.2 ε 33=50.7 ε 11=19.6 ε 33=76.5 ε 11=20.7 ε 33=79

Thermal expansion coefficient/(10-6/ºC) α 11=5.8, α 33=3.9 α 11=5.5, α 33=4.4 α 11=6.1, α 33=4.8

Piezoelectric strain constant d11=6.15 d14=-6.01 d11=7.41 d14=-6.16 d11=7.06 d14=-4.32

Electro optic coefficient pm/V γ 11=2.68, γ 41=1.22 γ 11=2.82 γ 11=2.62



Materials and product specifications:

Crystal materials LGS, LGT, LGN

Growth direction [001]

Size specifications (10 * 10~20 * 20) * (0.5~2) mm3

Transmittance~80%

Parallelism 30 arcsec

Smooth finish 20-10

Flatness λ/ eight

Wavefront distortion λ/ four

Effective aperture 90%

Collapse edge<0.1 mm

Chamfer<0.1mm × 45 °

Damage threshold>500 MW/cm