Introduction

Langatate – or “LGT” for short - is a piezoelectric crystal of the same crystal class as quartz. Its chemical formula is La3Ga5.5Ta0.5O14. Opposed to quartz it has no phase transition up to the melting point at about 1450°C. Therefore LGT is an excellent candidate for high temperature applications in piezoelectric sensors.

LGT has a piezoelectric factor d11, which is about 2.8 times that of quartz., which allows to realize piezo sensors with significantly higher sensitivity. The temperature stability of d11 and the isolation resistance are better than those of Langasite (LGS).

As the piezoelectric coupling factor is 2.3 to 3 times that of quartz, resonators with high frequency pullability (i.e. low capacitance ratio C0/C1) can be realized, having a temperature stability in the same order of magnitude as quartz resonators. The Q-factor of LGT overtone resonators is reported to be higher than with quartz. 

Langatate crystals are synthetically grown by the Czochralski method in boules up to 4" (100 mm) diameter. LGT has excellent thermal, piezoelectric and dielectric properties and is resistant to many chemicals.

The main applications of LGT include:

  • High-Temperature Surface Acoustic Wave (SAW) sensors
  • High-Temperature Bulk Wave (BAW) sensor
  • High -Temperature and Hiogh-Sensitivity Piezo-static sensor elements
  • Crystal units as Bulk Wave (BAW) resonators with high motional capacitance
  • SAW devices for frequency control and selection
  • Wideband piezoelectric filters, both discrete and monolithic

For more detais please consult our Technical Notes on Novel Piezoelectric Materials

Langatate (LGT) Blanks & Wafers

Langatate (LGT) La3Ga5.5Ta0.5O14 Wafers
Product

Diameter

[mm]

Thickness

[mm]

Cut

(Euler notation)

Surface

Quality

Flat

[mm]

Remarks
  76.2 0.500   SSP   SAW
  100 0.500   SSP   SAW
  76.2 0.500   DSP   BAW
             

Caption:
SSP = Single Side Polished. Back side fine lapped
DSP = Double Side Polished
SAW = Surface Acoustic Wave Device
BAW = Bulk Acoustic Wave Device

Other dimensions, cut angles and other parameters on request. Please contact AXTAL