Dear Ajay Manoharan ,

It is difficult to give a complete explanation without more details, explanations can change depending on the phases you are obtaining in the end. Can you give the formula of your lithium ferrite ?

i) It can be related to Lithium vaporization (above 800°C), meaning loss of stoechiometry, your materials then tends to transform into Iron related materials. It is observed in numerous Lithium materials (for example LLZO for batteries applications) when you apply a rather long heat treatment (+8 hours)

ii ) Phase transitions to other lithium ferrites polymorphs or metastable phases.

There is at least 3 reported polymorphs for LiFe5O8, see paper below :

Article Comparative study of the structural and magnetic properties ...

Kind regards,

Please read this article Chapter Lithium Ferrite: Synthesis, Structural Characterization and ...

Good luck