Figure 4
From: First experimental evidence of the piezoelectric nature of struvite
Strain η3 as a function of a.c. electric field strength E3 of frequency of 160 Hz at 300 K. To keep the crystal in thermodynamic equilibrium, slowly and continuous change of the E3 field with the rate of 0.075 kV/minute was applied. Since the electric field was applied in the direction [001], we have measured the d33 piezoelectric coefficient. The red straight line represents a fit to the relationship describing the piezoelectric effect η3 = d33 E3.
