Structurally Induced Spin Canting and Metamagnetism in CoFe2O4 Nanoparticles Synthesized via Co-precipitation Method

In the present manuscript, we have studied the structural and magnetic properties of CoFe2O4 nanoparticles synthesized at different pH levels (7, 10 and 12) via co-precipitation method. The structural analysis of the samples indicates the structural distortion at the octahedral site which has been found correlated with the observed roomtemperature magnetic moment of the CoFe2O4 nanoparticles. Magnetic studies reveal multiple magnetic phases and surface spin disorder in the samples. Spin canting/glass behaviour is also observed in the as-synthesized CoFe2O4 nanoparticles. In addition to these, the as-synthesized samples also show a novel metamagnetic transition due to the coexistence of antiferromagnetic and ferromagnetic ordering, simultaneously. The coexistence of antiferromagnetic and ferromagnetic phases is attributed to spin canting/surface spin disorder in the nanocrystalline samples. Mossbauer data also supports the presence of spin canting in the samples.