Study on Mössbauer Signature, Hyperfine Interaction Parameters and Removal of Delafossite Phase of Al3+-Modified Copper Ferrite

Abstract

The effect of Al 3+ substitution on Mössbauer signature and hyperfine interaction parameters of copper ferrite (CuFe 2 O 4 ) is studied at 300 K. The X-ray powder diffraction pattern analysis shows that all the four compositions of the ferrite system CuAl x Fe 2−x O 4 (x = 0.0, 0.2, 0.4, and 0.6) have single-phase fcc spinel structure. On the other hand, Mössbauer spectral analysis reveals that x = 0.0 and 0.2 compositions possess paramagnetic singlet of delafossite (CuFeO 2 ) phase along with two magnetic sextets of spinel ferrite phase. On Al 3+ substitution for Fe 3+ in the system (x ≥ 0.4), formation of this secondary unwanted phase of CuFeO 2 is found to be prevented. The hyperfine interaction parameters are determined and found to be influenced by Al 3+ substitution. The noncollinear spin arrangement in the system is verified and the actual cationic distributions are suggested.

Comprehensive Study on the Mechanism of Sulfating Roasting of Zinc Plant Residue with Iron Sulfates

“…The reduced values of the magnetic splitting for the sextets at room temperature and the high value of the resonance line width with a strong temperature dependence suggest that this is a poorly ordered and very defective phase [ 79 ]. It could be assumed that the group of the sextets ##1–3 also includes the group of copper ferrite sextets with ultrafine parameters close to the indicated oxides—CuFe 2 O 4 [ 80 , 81 , 82 , 83 ] or substituted analogs of copper ferrite Cu 1-x A x Fe 2-y B y O 4 , where A and B are a substituent element in the oxidation state +2 or +3, respectively, for example, Zn +2 [ 84 , 85 , 86 ], Cd +2 [ 85 ], Al +3 [ 87 ], Ga +3 [ 86 ]. However, this hypothesis was not confirmed because after calcination of these samples at 900 °C, no other iron-containing phases were found in the samples except for zinc ferrite and α-Fe 2 O 3 ( Appendix B ).…”