Effect of cation substitution on the magnetic and magnetotransport properties of epitaxial Fe3−xVxO4 films

The effect of cation on the structure, magnetic and magnetotransport properties of epitaxial Fe3−xVxO4 (0 ≤ x ≤ 0.6) films fabricated by reactive cosputtering was investigated systematically. Four kinds of cations (Fe2+, Fe3+, V2+ and V3+) exist in the Fe3−xVxO4 films. The Fe3−xVxO4 films reveal semiconducting property and increased resistivity with increasing V content. The systematic change of the decreased saturation magnetization and enhanced exchange bias is closely related to the spin canting and antiferromagnetic coupling, which is caused by the V substitution on B sites. The presents of V2+ (3d3) enlarge the anisotropy, and further increase the coercivity. With the combined effects of the larger anisotropy, spin canting and enhanced antiferromagnetic coupling caused by V substitution, the Fe3−xVxO4 films exhibit enhanced four-fold symmetric anisotropic magnetoresistance.