Gallium Orthophosphate - GaPO4 Benefits
High piezoelectric sensitivity
Even at room temperature, GaPO4 has twice the sensitivity of quartz. For thickness shear cuts it is even four times higher.
High thermal stability
Although GaPO4 is a quartz homeotypic crystal, there exists no a-b phase transition. Quartz loses its piezoelectric properties due to this phase transition at 573 °C, whereas GaPO4 does not change its high sensitivity up to temperatures above 700 °C.
Hydrothermally grown crystals show a high homogeneity and due the strong chemical bond of the oxygen atoms to the phosphorus atoms in the PO4 tetrahedron, which is much stronger than the bond between e.g. the relatively large Nb atoms and O in lithiumniobate, no outgassing has been observed in GaPO4.
Unlike other materials often used for high temperature applications (LiNbO3, LiTaO3, tourmaline), changes in GaPO4 do not cause interference to the sensor signals.
No spontaneous polarisation induced due to an electric field.
No stress induced twinning
No decrease of the sensitivity due to stress induced twinning. GaPO4 stays stable up to highest temperatures.
Less damping in fluids
Less damping of GaPO4 in fluids guarantees a higher sensitivity even at high temperatures.
Lower temperature dependence
Ferroelectric materials like LiNbO3 or LiTaO3 show a strong temperature drift of their resonant frequency. GaPO4 offers temperature compensated cuts for any operating temperature you need, with a lower temperature dependence than quartz.
Lower angular sensitivity
The resonant frequency of GaPO4 is less sensitive to the cut angle. For temperature compensation singly rotated Y cuts are being used.
Higher electromechanical coupling
Twice the coupling as quartz and about the same as langasite. This makes GaPO4 a very suitable material for VCXOs and SAW filters.
Because of the larger bandwidth of GaPO4, more information can be transmitted.
Larger pulling range
With a GaPO4 resonator, you can vary the resonant frequency within a wider range.
Lower insertion losses
The damping of surface acoustic waves in GaPO4 filters is much lower compared to other materials.
Lower SAW velocity
The lower SAW velocity of GaPO4 allows smaller SAW devices.