GaPO4 Stiffness and Piezoelectric Constants Measurements using the Combined Thickness Excitation and Lateral Field Technique

Anisotropy of the magnetoelectric effect in tri-layered composites based on single-crystalline piezoelectrics

“…Since all samples were prepared in the same manner, this seems to be in disagreement with the experiment, where we saw an almost four times smaller coefficient in the GPO structure. A likely explanation for this is the existence of a large discrepancy between the piezoelectric/dielectric coefficients of GPO found in the literature [22,24,35] and the actual properties of the commercial crystals, which are unknown to us.…”

“…Its constitutive elastostatic, electrostatic and magnetostatic equations were then solved assuming averaged homogeneous tensor fields in each perfectly elastically coupled layer (k C = 1) and under unclamped and open circuit boundary conditions. The linear anisotropic electric, magnetic and elastic material constants were obtained from the literature (Metglas [27][28][29], LNO [23], and α-GPO [22,24]). We note that a pseudopiezomagnetic approximation was assumed for the MS layer which is valid in the small region of the magnetostriction curve where the elastic strain (S i ) changes linearly with the applied bias field (H k ), and M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 the slope ∂S i /∂H k is maximized in such a way that S i = q ki H k where q ki denotes the piezomagnetic coefficient.…”

“…LNO is an uniaxial trigonal ferroelectric (point group 3m) with a very high Curie temperature of ca. 1150 o C [23], whereas GPO is a PE crystal with a trigonal structure (point group 32) and with a cristobalite transition at 933ºC [22,24]. Some desirable features of the two materials are their large ratio between piezoelectric and dielectric coefficients, excellent high-temperature properties, relatively low price, high chemical, thermal and mechanical stability, linear piezoelectric response, availability of high quality crystals and also a lead-free composition.…”

“…Besides LNO, a noteworthy piezocrystal for ME applications is gallium orthophosphate (GaPO 4 , GPO) [22]. LNO is an uniaxial trigonal ferroelectric (point group 3m) with a very high Curie temperature of ca.…”

Effect of Electrode Configuration on High Temperature Thickness Shear Gallium Phosphate Transducer

“…The principle function of the transducer is to enable single excitation and reception of waves which can only be achieved if the transducer has an appropriate broadband frequency response. A previous study on different crystal orientation of GaPO4 identified Y-cut to achieve a pure shear mode of vibration [2] and was therefore chosen for this study. To achieve a pure thickness shear mode of vibration and the desired frequency response from the GaPO4 element, its length (13 mm), width (3 mm) and thickness (0.5 mm) was chosen to provide an aspect ratio of 26 (>20 [3]) for this study.…”