Study of the Structural Characteristics of α- Alumina Doped with Different Cations

Three sets of α-alumina (α- Al2O3) doped with different cations
namely, Al2O3: xMnO, Al2O3: xMoO and Al2O3: xCdO have been prepared with
x ranges between 0.01 to 0.19 mol. The structure of the prepared samples was
refined by applying the full pattern fitting of Rietveld method using FullProf
program. It was found that the nonstoichiometric behaviour appeared from the
refinable value of the occupancy of Al site, reflects the amount of lattice defects
created in the samples. The amount of the dopant, incorporated into the host
alumina, depends not only on the ionic radii but also on the dopant valancy.
The effect of dopant concentration on the unit cell parameters has been
discussed on the basis of the amount of incorporated cations into the host
alumina. It was found, that the more occupancy of the dopant at Al-site, the
more the c/a ratio, the more is the distortion of the lattice.