Effect of barium lanthanum manganite nano particle on the electric transport properties of polypyrrole at room temperature

摘要

Barium lanthanum manganite (La0.7Ba0.3MnO3: LBM) synthesized by Sol-Gel method was studied as a composite material with organic conducting polymer polypyrrole (PPy) synthesized by in situ chemical oxidation method. Characterizations like SEM, TEM, FTIR and XRD were studied. Electrical conductivity and transport studies like dielectric constant, dielectric loss, complex electric and impedance modulus were analyzed using LCR impedance analyzer at room temperature in the frequency range 100Hz-5MHz. SEM and TEM images of LBM nano particle shows agglomerated orthorhombic structure, PPy forms clusters with spherical shape and PPy/LBM nano composites shows spherical structure with LBM embedded in PPy chain and with reduction of volume fraction. XRD of LBM shows the orthorhombic crystal structure, PPy confirms the amorphous nature and PPy/LBM nano composites shows semi crystalline phase. Electrical conductivity measurements of all the samples show relaxing behavior. Transport properties show good dielectric constant value with a very low dielectric loss for PPY/LBM nano composites than pure PPy. The highest dielectric constant value was observed for PPy/LBM40 nano composite the value being 171 at 10kHz corresponding dielectric loss is 0.43 which is less when compared to pure PPy having dielectric constant 130 at 10kHz and dielectric loss being 1.13. The complex electric and impedance modulus shows both grain and grain boundary effects. The study shows that by incorporating LBM nano particle in the PPy chain shows better value than as prepared PPy sample. Also when compared to our previous work on calcium doped lanthanum manganite (LCM) with polypyrrole as host the composite of PPy/LBM showed better electrical conductivity and transport properties. Thus incorporation of LBM nano particle to the PPy chain has resulted in the enhancement of electric transport properties. The present work reveals that the PPy/LBM nano composite can also be a promising material as an electrical storage device as well its application as an organic transistor.