The complex perovskite related cobalt oxides have recently drawn considerable attention among the scientific community due to their interesting physical properties owing to their multiple valence states. The Co electronic configuration, primarily determined by the crystalline electric field created by first-neighbor oxygen ions, plays a central role in tuning the physical properties of this class of compounds. In this work, we preset a detail investigation on the structural, microstructural, and broadband dielectric and magnetic properties of Al3+ doped Sr3YCo4O10+δ double perovskite oxides. The compounds were synthesized via conventional solid state ceramic route. A detailed analysis of crystal structure using XRD and FTIR, microstructure using SEM and cobalt valence states using XPS, broadband electromagnetic response and room temperature magnetic property of the compounds will be presented. XRD analysis confirmed that all the compounds crystallize in I4/mmm symmetry indicating that Al3+ substitution doesn’t alter the crystal symmetry of the parent compound. XPS analysis confirmed that the Co3+/Co2+ ratio increases with increase in Al3+ concentration. The broadband dielectric and magnetic properties of the double perovskites were correlated qualitatively to the multiple valence state of the cobalt ions. The real part of permittivity found to be decreased with increase in Al3+ concentration while the dielectric loss found to be increased. The real part of permeability decreased accompanied by a decrease in the magnetic loss factor with an increase in Al3+ concentration. Further, impedance analysis revealed the capacitive behavior of the compounds while room temperature magnetic measurements using VSM revealed the diminishing ferromagnetic nature of the parent compound with the substitution of aluminum ions due the reduction in oxygen vacancy ordering.

Influence of Al3+ substitution on the crystal structure, microstructure and broadband electromagnetic properties of Sr3YCo4O10+δ double perovskite

ACS Spring Meeting 2021

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