Manganese ferrite (MnFe2O4) is a mixed spinel in which on the average 20% of Mn2+ ions reside on the B sites (Octahedral sublattice), when prepared by conventional growth techniques. Recently, we have devised a growth scheme by which the percentage of the Mn2+ ions on the B sites can be artificially controlled. The lattice constant and chemical composition of the artificial ferrite films were the same as that a bulk spinel ferrite or MnFe2O4, but the magnetic properties, exchange constants, Neel temperature, saturation magnetization and magnetic anisotropy field were very different from that of a typical bulk MnFe2O4. In this proposal, our aim is to explore the ability to affect magnetic ion distributions of a spinel structure of given composition to prepare (1) artificial ferrites with enhanced saturation magnetization and (2) to devise a systematic approach to design ferromagnetic spinel ferrites.
Fundamental research on magnetism and/or ferrite materials has been declining, although world markets depend heavily upon ferrite materials. We believe that our research will have a broad impact to the ferrite community and the scientific community at large. Our growth technique marks a significant departure from traditional or conventional procedures in preparing spinel ferrites in the following sense. The distribution of magnetic ions within a unit cell of a spinel ferrite can now be artificially controlled by growth techniques developed by us. This implies improved magnetic sensors, smaller and efficient microwave and electronic devices for computer and wireless communication applications.
