Optical properties induced and ferroelectric properties enhanced of the PMN-32PT:Ho relaxor ferroelectric crystals

Relaxor ferroelectric crystals PMN-32PT:Ho were prepared by using the flux method. Phase structure and surface morphology of the crystals were performed by using the X-ray diffraction analysis (XRD) and scanning electron microscope (SEM), respectively. A broad dielectric peak in temperature dependent of dielectric spectrum was observed during the phase transition of the PMN-32PT:Ho crystals. The modified Curie-Weiss and Lorentz-type laws were used to describe the dielectric relaxor behavior of the crystals. Optical performances were characterized by using the fluorescence spectrophotometer, Fourier transform infrared spectroscopy (FTIR) and ultraviolet spectrophotometer. Effects of Ho3+ modification on structure, dielectric relaxation, ferroelectric and optical properties of the PMN-32PT crystals were investigated. Ferroelectric properties were improved and the larger coercive field EC was found to be 4.31 kV/cm at room temperature by the Ho modification. Optical performances of the PMN-PT crystals could be induced by the introduction of the Ho ions. The green light of 550 nm and red light of 630 nm were emitted under the excitation at 465 nm. The mechanism of the up-conversion luminescence for as-grown crystals was also discussed.