Lithium Niobate
Physical Properties
| Property | Value |
|---|---|
| Molecular Weight | 147.85 |
| Density | 4.65 g/cm3 |
| Crystal Class | Rhombohedral |
| Moh's Hardness | 5 |
| QM | Approx. 10000 |
| QE | 1000 |
| Melting Temperature | 1253°C |
| Curie Point | 1150°C |
| Thermal Expansion (@ 25°C) | 15.4 x 10-6 /°C parallel to C-axis in a temperature range from 0°C to 110°C. 7.5 x 10-6 /°C perpendicular to C-axis in a temperature range from 0°C to 110°C |
| Thermal Conductivity (@ 25°C) | 1 x 10-2 cal/(cm/sec/°C) |
Piezoelectric & Dielectric Properties
| Property | Value |
|---|---|
| Piezo Strain Constants | |
| (x 10-12 C/N) | (C/m2 ) |
| d15 = 69.2 | e15 = 3.83 |
| d22 = 20.8 | e22 = 2.37 |
| d31 = -0.85 | e31 = 0.23 |
| d33 = 6.0 | e33 = 1.3 |
| Piezo Pressure Constants | |
| (x 10-2 m2 /C) | (x 109 N/C) |
| g15 = 6.92 | h15 = 9.5 |
| g22 = 2.8 | h22 = 6.4 |
| g31 = -0.4 | h31 = 0.8 |
| g33 = 2.3 | h33 = 5.1 |
| Dielectric Constants | |
| εS11/ε0 = 44.3 | εT11/ε0 = 85.2 |
| εS33/ε0 = 27.9 | εT33/ε0 = 28.7 |
Elastic Constants
| Constant | Value |
|---|---|
| Young's Modulus | 2.93 x 107 PSI parallel to C-axis 2.63 x 107 PSI perpendicular to C-axis |
| Modulus of Rigidity | 1.04 x 107 PSI parallel to C-axis 1.09 x 107 PSI perpendicular |
| Compliance Constants ( x 10-12 m2 /N) | |
| SE11 = 5.831 | SD11 = 5.20 |
| SE12 = -1.150 | SD12 = -0.44 |
| SE13 = -1.452 | SD13 = -1.45 |
| SE14 = -1.000 | SD14 = 0.87 |
| SE33 = 5.026 | SD33 = 4.89 |
| SE44 = 17.10 | SD44 = 10.8 |
| SE66 = 13.96 | SD66 = 11.3 |
| Elastic Constants ( x 1011 N/m2) | |
| CE11 = 2.030 | |
| CE12 = 0.573 | |
| CE13 = 0.752 | |
| CE14 = 0.085 | |
| CE33 = 2.424 | |
| CE44 = 0.595 | |
| CE66 = 0.728 | |
Optical Properties
| Property | Value |
|---|---|
| Birefringence | No - Ne = 0.085 +/- 0.001 |
| Refractive Index @ 0.6328 Å | No = 2.2868 Ne = 2.2030 |
| Transmission Range | 0.4 µm - 5.0 µm |
Direction Dependent Properties and Constants
| Orientation | Wave Type | Wave Speed (m/s) | Coupling Factor |
|---|---|---|---|
| 36° Rotated Y-cut | Quasi-longitudinal | 7340 | .485 |
| 163° Rotated Y-cut | Quasi-shear | 4528 | .612 |
| 10° Rotated Y-cut | Quasi-longitudinal / Quasi-shear | 7063 / 4271 | .472 / .436 |
| 41° X-cut | Shear | 4795 | .684 |
| Z | Longitudinal | 7316 | .162 |
| Y-Z | Surface | 3488 | .045 |
| 128°-X | Surface | 3992 | .053 |
Reference Material
A very good reference is in The Journal of the Acoustical Society of America, Volume 42, Number 6, 1967, Page 1223: "Determination of Elastic and Piezoelectric Constants for Crystals in Class (3m)", by A. W. Warner, M. Onoe, and G. A. Coquin.
