Spinel Ferrite/MnO Core/Shell Nanoparticles: Chemical Synthesis of All-Oxide Exchange Biased Architectures

摘要

Exchange coupling between ferromagnetic (FM) and antiferro-magnetic (AFM) phases in composite materials is of great interest for technological applications.These materials find extensive use as read-heads in modern high-density magnetic storage disks.FM-AFM exchange coupling was first observed in 1956 by Meiklejohn and Bean in partially oxidized Co nanoparticles (10-100 nm).They observed that when the particles were field-cooled across the Neel temperature (T_N) of CoO an exchange bias occurred,which resulted in a shifted hysteresis loop and increased coercivity.