Pure-mode measurements of dilithium tetraborate material properties

The full set of elastic, piezoelectric, and dielectric constants of dilithium tetraborate (Li₂B₄O₇), along with the mass density, have been measured at room-temperature using the resonator method. The sample orientations used in the measurements were selected to maximize accuracy and precision through (1) the use of an overdetermined data set with critical self consistency checks, and (2) the use of pure-mode vibrations for which exact, analytic expressions for the piezoelectrically stiffened elastic stiffness eigenvalues exist. The experimental program included measurements of the physical dimensions, masses, critical frequencies, and capacitance of the various samples. The set of material constants obtained in this work are, on average, 2x to 10x more accurate in reproducing the measured data when compared to the previously reported sets of material constants.