Enhancement of Curie Temperature and Photoluminescent Properties of Ho1.98sm0.02sn2o7 and Ho1.90er0.10sn2o7 Smart Materials

Abstract

Ho2Sn2O7 powders doped with Er3+ and Sm3+ were directly synthesized using a solid state reaction method. Ho1.98Sm0.02Sn2O7 and Ho1.90Er0.10Sn2O7 were investigated using a TG/DTA thermal analysis system, scanning electron microscope (SEM), photoluminescence spectrophotometer (PL), X ray diffractometer (XRD), d33-meter and LCR-meter. As a result of the analyses, the thermal behaviour, crystal system, morphological structure, photoluminescence properties, elemental analysis, dielectric constant, piezoelectric properties and loss tangent of Ho1.98Sm0.02Sn2O7 and Ho1.90Er0.10Sn2O7 were obtained and discussed. According to XRD, the unit cell parameters for single-phase pyrochlores with a cubic crystal system are a = b = c = 10.374 & Aring; and alpha = beta = gamma = 90 degrees. The XRD patterns demonstrate that neither the type nor the amount of doping ion alters the unit cell parameter. The SEM images of Ho1.98Sm0.02Sn2O7 and Ho1.90Er0.10Sn2O7 reveal a regular morphology, with an average sample size ranging from 0.2 to 0.9 mu m. The EDX analysis confirm the absence of impurity elements and showing that the theoretical and experimental element ratios are consistent with EDX analysis expectations. The emission spectrum of Ho1.98Sm0.02Sn2O7 and Ho1.90Er0.10Sn2O7 were shown typical transitions of Sm3+ and Er3+, respectively. Ho2Sn2O7 doped with Sm3+ was found to yield a high dielectric constant (73.93), a high piezoelectric charge constant (0.75 pC/N), and a higher Curie temperature (772 degrees C). This suggests that Sm3+ ions enhance the Curie temperature and piezoelectric properties when introduced into the Ho2Sn2O7 host crystal. The results indicate that Ho1.98Sm0.02Sn2O7 and Ho1.90Er0.10Sn2O7 are smart materials with multi-functional which have both piezoelectric properties and photoluminescent properties.