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The effect of partial substitution of Pd in LaMnO3 polycrystalline materials synthesized by sol–gel technique on the electrical performance

  • Paula SfirloagaEmail author
  • Iosif Malaescu
  • Catalin Nicolae Marin
  • Paulina Vlazan
Original Paper: Characterization methods of sol–gel and hybrid materials
  • 12 Downloads

Abstract

This work reports the change in the structural and electrical behavior of partial substitution of manganese by palladium in LaMnO3 perovskite materials synthesized through sol–gel method. X-ray diffraction analysis reveals that all the obtained materials crystallize in the orthorhombic perovskite structure (Pnma space group). Morphological investigations show the presence of fine nanometric particles of similar shape and high tendency to agglomerate, and the elemental analysis highlights the presence of palladium. Detailed study of complex impedance measurements in the frequency range 20 Hz–2 MHz and different temperatures between (30 and 120) °C indicate the presence of electrical relaxation in materials; the activation energy of relaxation decreases from 0.207 eV (0.05% Pd–LMO–Pd1) to 0.102 eV (0.15% Pd–LMO–Pd3) when the x concentration of Pd increases from 0.05 to 0.15. The electrical conductivity analyses indicate that the conduction mechanisms in the low-frequency range (f < 100 kHz) are activated thermally and were explained using the Mott’s variable-range-hopping (VRH) model. In the high-frequency range (f > 100 kHz), the conduction mechanism is due to the charge carriers hopping between the nearest neighboring states, in agreement with the CBH model (correlated barrier hopping). Based on this model, the bandgap energy, Wm was determined. The results show that by increasing the Pd concentration, the value of Wm of the sample increases, from 0.229 eV (LMO–Pd1) to 0.298 eV (LMO–Pd3), in agreement with the decreasing of electrical conductivity of samples.

Highlights

  • Partial substitution of Mn by palladium in LaMnO3 perovskite materials.

  • Heat treatment was performed at low temperature.

  • Detailed studies of impedance and electric conductivity have been performed.

Keywords

Sol–gel Perovskite Palladium Electrical properties 

Notes

Acknowledgements

Financial support for this work was provided by the Experimental Demonstrative Project 48PED/2017 and Nucleu National Project PN 19220201, Ctr. 40 N/2019. The authors thank D. Ursu for help during the materials characterization.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Paula Sfirloaga
    • 1
    Email author
  • Iosif Malaescu
    • 2
  • Catalin Nicolae Marin
    • 2
  • Paulina Vlazan
    • 1
  1. 1.National Institute for Research and Development in Electrochemistry and Condensed MatterTimisoaraRomania
  2. 2.West University of TimisoaraTimisoaraRomania

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