Relaxor based ferroelectric single crystals, such as Pb(Mg1/3Nb2/
3)O3-xPbTiO3 (PMNT or PMN-xPT) and Pb(Zn1/3Nb2/3)O3-xPbTiO3(PZNT
or PZN-xPT) have triggered revolutionary changes in piezoelectric devices
over the past few decades. This is because of their ultrahigh electromechanical
coupling factor k33 (N94%) and piezoelectric constant
d33 (N2500pC/N) near the morphotropic phase boundary (MPB) at
room temperature [1–5].
One of the drawbacks of PMNT single crystals is their relatively low
Curie temperature (Tc ≈ 130 °C) and phase transition temperature
(TrT ≈ 85 °C) from the rhombohedral to tetragonal phase, which limits
their high temperature applications. Recently, a ternary compound
Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIMNT or PIN-PMN-xPT)
has attracted great attention because it exhibits a higher Tc (≈200 °C)
and TrT (≈110 °C) with comparable piezoelectric performance to that
of PMNT single crystals [6–7].
The authors have previously achieved a large K2 (≈60%) by fabricating
a SAWresonator on YX-PIMNT substrate [8–9].However, the barrier
to its application in radio frequency (RF) SAWfilters is its lowphase velocity
(≈1350 m/s) that results in low resonance frequency fr
(≈355MHz) at a wavelength λ≈4 μm. The direct approach to achieve
higher frequency operation is to reduce the width of the electrodes, but