A detailed analysis on the morphological, optical and electrical characteristics of PZN-PT single crystals

Relaxor ferroelectric single crystals of (1-x)Pb(Zn1/3Nb2/3)O3−xPbTiO3, (PZN-PT) of two different compositions ( x=8% & 9%) were grown by high temperature self flux method. The compositions of ‘x’ were chosen to be near the morphotropic phase boundary. Different orientations of rhombohedral and tetragonal domains and their coexisting phases for PZN-9%PT were confirmed from the images of polarized light microscopy. The presence of domain walls and strip like structures on the surface was observed using atomic force microscope. Refractive index was found to be 2.6 and 2.57 for PZN-9%PT and PZN-8%PT crystals respectively. Temperature dependent Raman scattering studies clearly indicate the structural phase transitions from rhombohedral to tetragonal and finally to the cubic phase upon heating. Curie temperature was found to be around 452 K and 446 K PZN-9%PT and PZN-8%PT crystals respectively. Presence of Raman bands even after the phase transition in both the samples evidence that no long-range ferroelectric order is established. Ferroelectric behaviour of PZN-PT crystals was confirmed from the butterfly like C-V curves for frequencies ranging from 10 kHz to 100 kHz. It was observed that PZN-9%PT exhibits higher capacitance when compared to PZN-8%PT.