DIELECTRIC PROPERTIES OF La0.67Sr0.33Mn1-xTixO3 WITH x = 0.4 and 0.6

Abstract

The dielectric properties of Ti-substituted La_0.67Sr_0.33Mn_1-xTi_xO₃ with x = 0.4 and 0.6 as a function of frequency and temperature have been investigated. The samples have been prepared using the conventional solid state reaction method at 1300^oC. Both samples showed rhombohedral structure with R3C space group. The grain size of x = 0.4 and 0.6 are ~2.5 to 3.3 μm and ~0.4 to 0.9 μm respectively. The dielectric constant, ε' of the samples decreases with frequency but increases with temperature. We have successfully obtained very high dielectric constant material. The highest ε' value for LSMT with x = 0.4 and 0.6 are at frequency of 10 Hz and temperature 300 K, which are ~5.7 x 106 and ~2.4 x 106. The tan δ increases with temperature for x = 0.6 but shows a peak at a certain temperature for x = 0.4. Sample with x = 0.4 has better dielectric properties compared to x = 0.6 sample because it has higher ε' and lower tan δ value. At 175 K and 1 kHz sample with x = 0.4 shows the best dielectric properties with a high ε’ value and low tan δ which are 1.1 x 105 and 0.8 respectively.