Composition uniformity of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals grown in 〈0 0 1〉 direction

Abstract

As a typical representative of the second generation of relaxor-PbTiO3 (PT) ferroelectric single crystals, Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals exhibit an improved thermal stability of piezoelectric properties compared with PMN-PT single crystals. The high quality and large-size PIN-PMN-PT single crystals are required for transducers. Composition segregation inevitably exists in relaxor-PT ferroelectric crystals grown by the vertical Bridgman method, resulting in poor uniformity of piezoelectric properties. The single crystal boule grown in 〈001〉 direction have the best composition uniformity. In this work, the composition uniformity of PIN-PMN-PT single crystals grown in 〈001〉 direction was investigated. The PT content varies from 31 mol% to 35 mol% from the bottom to the top of crystal boule. The TR/M−T decreases gradually from 113 °C to 73 °C and TC increases from 155 °C to 184 °C respectively. Optimizing the poling condition, the dielectric and piezoelectric properties of 80% of the single crystal boule can keep consistent.The free dielectric constant ε33T/ε0 and piezoelectric coefficient d33 are 4500–5000 and 1700–1900 pC/N, respectively, showing the improvement of theutilization of crystal boule.