Structural and electrical properties of monovalent K doping in Pr0.6(Sr1-xKx)0.4MnO3 polycrystalline ceramics

Pr-0.6(Sr1-xKx)(0.4)MnO3 polycrystalline ceramics (PSKMO, 0 <= x <= 0.25) were fabricated via using sol-gel method. The structure of PSKMO ceramics was identified to be the orthorhombic structure with Pnma space group. As K-concentration (x) rose, grain sizes increased significantly. The constituent elements of PSKMO ceramics were uniformly distributed on the surface. From the resistivity dependence of temperature (rho-T) curves, it was clear that resistivity rose with the increase of K-concentration. Notably, the peak temperature coefficient of resistivity (TCR) and temperature (T-k) decreased as x rose in this study. This result was attributed to the disorder of cation size on A-site (sigma(2)), which induced lattice strain leading to the random displacement of O2- ions. Further, it led to the distortion of MnO6 octahedron that promoted the localization of electrons, thereby reducing T-k. Moreover, the maximum value of TCR reached 7.60% K-1 at 299.31 K (for x = 0.15). This result suggested that the Pr-0.6(Sr0.85K0.15)(0.4)MnO3 ceramic was befitting for application in advanced uncooled infrared bolometers.

Automated summary

Pr-0.6(Sr1-xKx)(0.4)MnO3 polycrystalline ceramics (PSKMO, 0 <= x <= 0.25) were prepared using the sol-gel method. The PSKMO ceramics exhibited an orthorhombic structure with Pnma space group. As the K-concentration increased, the grain sizes also increased significantly, and the constituent elements were uniformly distributed on the surface. The resistivity of the ceramics increased with the increase in K-concentration. Moreover, the TCR and T-k decreased with increasing x, which was attributed to the disorder of cation size on the A-site and the distortion of MnO6 octahedron, resulting in the localization of electrons and a reduction in T-k. The highest TCR value reached 7.60% K-1 at 299.31 K (for x = 0.15), suggesting the suitability of Pr-0.6(Sr0.85K0.15)(0.4)MnO3 ceramic for advanced uncooled infrared bolometers.