Abstract

Synthesis and Characterization of Rare Earth doped Nanoparticles for electrical and Dielectric properties

Author(s): Tarannum Vahid Attar* and Mahendra M. Khandpekar

This paper deals with the measurement of dc conductivity and the dielectric constant of the LaF3: Pr3+,Ho3+nanoparticles using sophisticated Hioki 3532 LCR Meter. For this, doped LaF3: Pr3+,Ho3+nanocrystals have been successfully synthesized by microwave assisted technique using deionised water as solvent. The X-ray diffraction, SEM, TEM and selected area electron diffraction SAED pattern have been used for identification of crystal structure. Synthesized nanocrystals are found to belong to hexagonal crystal system with space group P3c1 and lattice parameters a = b = 7.080 A0and c = 7.238 A0. Using Scherrer equation average particle size has been estimated which is found to be 11.17nm. SEM pattern shows dispersed, hexagonal, discs like, assorted particles with traces of some aggregates. SAED pattern indicates formation of strong diffraction rings corresponding to the (110), (111), (300), and (221) reflections which is in agreement with the hexagonal LaF3 structure. Nanocrystals of hexago-nal geometry with particle size 15nm have been traced by TEM analysis which is in agreement with the average crystalline size obtained from XRD studies (11.17nm). The dielectric studies shows that the ε' and ε" falls rapidly withapplied frequency. Both ε'and ε"exhibit normal dielectric behaviour. Graph of log ε" vs log frequency shows near linear nature and graph of Tanδ vs log frequency shows that there is decrease in Tanδ with increasing value of frequency. This nature is attributed to the interface charge relaxation at the grain boundaries. The conductivity of the synthesised LaF3: Pr3+, Ho3+nanocrystals at room temperature is found to be 1.565 x 10-3/Ωcm. Thus by doping LaF3the ionic conductivity of the sample is observed to be enhanced as compared to the conductivity of pure LaF3having conductivity of the order of 10-6/Ωcm. Resistivity at room temperature is found to be 638.977Ωcm.

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