Synthesis And Properties Of Tetragonal Relaxor Ferroelectric Single Crystals Erbium Doped Lead Indium Niobate-Lead Magnesium Niobate-Lead Titanate

Ternary lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT) single crystalsystem have been extensively studied for its novel dielectric, piezoelectric and electromechanicalproperties among relaxor-based ferroelectric materials, and exhibit much more excellentperformance，especially in the field of new piezoelectric materials for the next generation of highperformance micro actuators and ultrasound transducers. PIN-PMN-PT single crystals doped witherbium near the morphotropic phase boundary (MPB) inherits the excellent properties of thePIN-PMN-PT single crystal system, such as high compositional homogeneity and high structuralquality properties. Based on optical and electric research methods, we have performed investigationson piezoelectric properties, phase transition, phase structure, energy band strcture of erbium dopedPIN-PMN-PT single crystal.A new kind of lead indium niobate-lead magnesium niobate-lead titanate crystal doped with erbium(0.24PIN-0.43PMN-0.33PT-0.02Er2O3) was grown by a modified Bridgman method. Thegrown-crystal has the size of25×65mm and be poled and processed with sophisticated technology.The resonance-antiresonance frequencies method was used to determine some elastic, piezoelectric,dielectric and electromechanical constants of erbium doped PIN-PMN-PT single crystal. The P-Eloop of (001),(011),(111)-cut Er-PIN-PMN-PT single crystal was measured and the remnantpolarizations and the coercive fields were higher than pure PIN-PMN-PT single crystals. The samplehas maximum remnant polarization of50μC/cm2and maximum coercive field of720V/mm fordifferent oriented crystals. The structural phase transition characteristic was also studied by using thedielectric constant versus temperature and bidirectional field induced strain curve.The upconversion fluorescence spectrum of erbium doped PIN-PMN-PT single crystal pumped by980nm laser was measured. The transmission spectra were investigated and the difference between thetransmittances of crystals poled in different orientations can be explained with the ferroelectricdomain structures.When poled along [011]c, the transmittance of the crystal enhanced dramatically toabout67%. The refractive indices of Er-PIN-PMN-PT single crystal were measured accurately withelliptic polarization spectrometer in different orientations. The parameters in Sellmeier’s equations ofrefractive indices for Er-PIN-PMN-PT were obtained by terms of the least-squares fitting method.Based on the theory of band to band transition, the direct and indirect energy bandgap of Er-dopedPIN-PMN-PT single crystal were calculated with the transmittances and refractive indices of thecrystal.