Processing stages of Gd ₂ Sr(Al _{1− <i>x</i>} Fe _<i>x</i> ) ₂ O ₇ series

Abstract The continuous series of perovskite‐related oxides with the general formula Gd 2 Sr(Al 1− x Fe x ) 2 O 7 0 &lt; x &lt; 1 were prepared by conventional ceramic technology in air. The processing stages of Gd 2 Sr(Al 1− x Fe x ) 2 O 7 0 &lt; x &lt; 1 phases were investigated by means of X‐ray powder diffraction (XRD) and scanning electron microscopy (SEM) with the element phase analysis. The three main stages of Gd 2 Sr(Al 1− x Fe x ) 2 O 7 formation are pointed out. The analysis of the mutual influence of intermediate compounds on the synthesis of the target solid solutions of complex composition, in particular for Gd 2 Sr(Al 1− x Fe x ) 2 O 7 was carried out. It is determined that the closeness of the reactive mixture composition to the composition of individual compounds Gd 2 SrAl 2 O 7 or Gd 2 SrFe 2 O 7 is of importance for the realization of a particular way of Gd 2 Sr(Al 1− x Fe x ) 2 O 7 solid solutions formation. It is shown that at x ≈ 0.2 the reversing in scheme of Gd 2 Sr(Al 1− x Fe x ) 2 O 7 series formation is observed. The formation of the Gd 2 Sr(Al 1− x Fe x ) 2 O 7 continuous series is indicated by the monotonic dependence of molar unit cell volume on the iron content x .

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