Evolution of ferrimagnetism in Co(Cr1−xAlx)2O4(x=0.0−1.0)

• Study of preparation, structural and magnetic properties of Co(Cr1−xAlx)2O4(x=0.0−1.0)Co(Cr1−xAlx)2O4(x=0.0−1.0).
• Observation of enhancement in the magnetization up to 50% of Al substitution and reduction beyond 50% Al substitution.
• Influence of the non-magnetic Al substitution on the various magnetic phase transitions in CoCr2O4 and importance of Cr-site.
• Plausible explanation for these variations in the magnetic properties of Co(Cr1−xAlx)2O4Co(Cr1−xAlx)2O4.

Here we report on the preparation, structural and magnetic properties of solid solutions of Co(Cr1−xAlx)2O4Co(Cr1−xAlx)2O4. Substituted Al ions are found to occupy the B-site of the spinel structure. Enhancement in the magnetization is noticed up to 50% of Al substitution, beyond which it decreases. Further, the decrement in ferrimagnetic ordering temperature is observed on gradually introducing the non-magnetic Al into magnetic Cr-site. All these variations in the magnetic properties of Co(Cr1−xAlx)2O4Co(Cr1−xAlx)2O4 are ascribed to the reduction of the magnetization of B-site and weakened conical spin-spirals of the CoCr2O4 with the Al substitution.