Positron annihilation spectroscopic studies of multiferroic Bi1-xPrxFeO3 nanocrystalline compounds

11th International Workshop on Positron and Positronium Chemistry

物理学;化学

Cyriac, Jincemon^1,2 ; Rahul, M.T.^1 ; Kalarikkal, Nandakumar^1,3 ; Nambissan, P.M.G.^4

School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala

686560, India^1

Department of Physics, Devamatha College, Kuravilangad, Kottayam, Kerala

686633, India^2

International and Inter University, Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam, Kerala

686560, India^3

Applied Nuclear Physics Division, Saha Institute of Nuclear Physics, Kolkata

700064, India^4

关键词: Cationic vacancy;    Coincidence doppler broadening;    Ionic radius;    Multiferroics;    Nanocrystalline compounds;    Positron lifetime;    Positron trapping;    Spectroscopic studies;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/618/1/012012/pdf
DOI  :  10.1088/1742-6596/618/1/012012

来源: IOP

【 摘 要 】

Positron lifetime (PL) and coincidence Doppler broadening spectroscopic (CDBS) experiments were carried out on BiFeO3samples doped with Pr(in place of Bi) in concentrations (x) = 0, 0.05, , 0.35. In the initial stages of doping, the existing Bi3+vacancies are occupied by Pr3+ions and positron trapping is reduced. From x = 0.15 to 0.35, more number of positrons diffused to the surfaces of the nanocrystallites. The CDBS ratio curves showed enhancement of the peak at pL= 10.2×10-3m0c due to positron annihilation with the 2p electrons of oxygen. It suggested increased trapping of positrons in newly created cationic vacancy-type defects due to the mismatch of ionic radii of Pr3+substituting Bi3+ions. The lattice parameters decreased (3.9661-3.9248Å) while the nanocrystallitesizes reduced and increased (28.6-34.2nm) during the doping.