Bi-magnetic materials possess unique magnetic characteristics combining hysteretic and built-in responses for self-bias magnetoelectric applications. In this work, two bi-magnetic clusters of Co/MFe2O4 (M = Co and Zn) were hydrothermally synthesized for relative comparison of magnetic characteristics between ferromagnetic/ferrimagnetic (Co/MFe2O4) and ferromagnetic/antiferromagnetic (Co/MFe2O4) complexes. Both bi-magnetic clusters were found to exhibit clear two-phases with random morphology and average cluster size of 110 nm via physical complexation. Magnetic characteristics of the Co/MFe2O4 and Co/MFe2O4 illustrated M-H slope of 0.02 emu/g Oe at H-dc = 0 Oe with different remanent magnetization of 15.16 emu/g and 0.22 emu/g, respectively. As a magnetostritive phase in the magnetoelectric composites, two bi-magnetic clusters were formed with uniform cluster size for effective strain transfer between magnetostrictive-piezoelectric phases in the magnetoelectric system. (C) 2017 Elsevier Ltd. All rights reserved.