Micro-Structural, Thermal, Optical and Physical Properties Nanocrystalline NbSr_2Pr_(1.5)Ce_(0.5)Cu_2O_(10-δ) Material Synthesized by Mechano-Thermal Method

摘要

We have prepared nanocrystalline NbSr_2Pr_(1.5)Ce_(0.5)Cu_2O_(10-δ) (Nb1222Pr) material by annealing the ball milled powder at 1000°C for 24h and studied by various characterization techniques such as TG-DTA, XRD, FT-IR, NIR, SEM-EDX, magnetization and electrical resistivity. Significant difference is seen in the TG-DTA curves of the as-milled powder due to ball milling. The annealed Nbl222Pr material is crystallized in tetragonal symmetry with lattice parameters, a = 0.3887(3) nm and c = 2.878(2) nm with reduced average particle size of ～42.67 nm. Agglomeration of fine spherical particle sizes in the range of ～180 - 280 nm is seen through SEM micro-image. The variation in the crystalline sizes of the Nb1222Pr phase obtained from XRD and SEM image indicate the polycrystalline characteristic of fine nanocrystalline particles. Neither superconductivity nor magnetic ordering is seen for the Nb1222Pr phase down to 5 K under 100 Oe. The four probe resistivity measurement reveals the semiconducting behavior of the Nb1222Pr phase.