Exchange bias in bismuth ferrite/cobalt ferrite Janus nanofibers

Bismuth ferrite: cobalt ferrite (BiFeO3: CoFe2O4) nanofibers with tailorable exchange bias effects were synthesized utilizing a Janus type morphology, wherein both phases are coupled longitudinally along the length of each fiber. By varying the relative phase amounts of BiFeO3 and CoFe2O4 of the fibers, the interfacial area between the phases could be tuned and thereby the magnitude of exchange bias effects could also be tuned. Each BiFeO3: CoFe2O4 wt% fiber system exhibited characteristic exchange bias effects, specifically increased anisotropy and coercivity. HE, the magnitude of the shift in the center of the field cooled hysteresis loops, was found to have a direct relationship with interfacial area with a similar minimum for a 50 : 50 wt% sample and maximized as either phase weight percent was decreased.