Basic Properties
Langasite crystal possesses some great properties, such as higher electromechanical coupling factor than quartz, no phase transition from room temperature to melt point. Some properties of langasite crystal are shown in Table 1 and Table 2.
With the rapid development of the communication technology, the new generation communication system enables people not only to talk, but also to transmit image, data and video. Langasite crystal possesses high SAW properties compared with quartz, which make it to be the most competitive material in this field. SAW properties of langasite and quartz are listed in the Table 3.
Products Information
Diameter |
10~100 mm |
Thickness |
0.13~0.5 mm |
First Reference Flat |
15.0 mm |
Second Reference Flat |
8.0 mm |
Surface Roughness |
Ra≤1 nm |
Orientation |
following customer specifications |
Other sizes reflected in customer specifications |
Table 1 Dielectric, piezoelectric, elastic stiffness constants and their first order temperature coefficients of langasite crystal
Constant |
Relative |
Piezoelectric Constant |
Elastic Stiffness(1011 Pa) |
|||||||
11 |
33 |
d11 |
d14 |
c11 |
c12 |
c13 |
c14 |
C33 |
C44 |
|
Value |
18.96 |
50.19 |
5.66 |
-5.48 |
1.898 |
1.058 |
1.022 |
0.144 |
2.626 |
0.535 |
First Order Temp. Coef.(10-6K-1) |
150 |
-760 |
329 |
-342 |
-66 |
204 |
-75 |
-335 |
-94 |
-63 |
Table 2 Comparative properties of piezoelectric crystals
Properties Crystal |
Quartz SiO2 |
Langasite |
Lithium tetraborate Li2B4O7 |
Lithium tantalate LiTaO3 |
Electromechanical Coupling Factor K, %(BAW) |
7.0 |
15.8 |
24.0 |
47.0 |
Frequency Spacing f, % |
0.25 |
0.90 |
4.00 |
7.00 |
Q-Factor Q, ×103 |
100 |
50 |
10 |
2 |
Temperature Frequency Coefficient |
0.5 |
1.6 |
6.0 |
4.0 |
Table 3 SAW properties of langasite and Quartz
Properties Crystal |
Quartz (SiO2) |
Langasite (La3Ga5SiO14) |
Density, g/cm |
2.65 |
5.746 |
SAW Velocity Vef, m/s |
(0°, 132.75°, 0°) |
(0°, 140°, 25°) |
Electromechanical coupling factor K2emc, %(SAW) |
0.14 |
0.36 |
Second order temp. coef. |
-3.2 |
-6.8 |
Temp. Coef. TTO, ℃ |
25 |
23 |