Structural phase change in Co2.25Fe0.75O4 spinel oxide by vacuum annealing and role of coexisting CoO phase on magnetic properties

M(H) loop of vacuum annealed CoFe8V4 samples (a-e) and air annealed CoFe8A4 sample (f-g) at selected measurement temperatures. The variation of exchange bias field with temperatures for both the samples (h).238