Oscillatory exchange coupling and giant positive magnetoresistance in TiN/Fe3O4 superlattices

Oscillatory exchange coupling is observed in TiN/Fe3O4 superlattices over length scales comparable to metallic superlattices. However, the strength of the coupling is almost an order of magnitude stronger than that commonly observed in metallic superlattices. In addition, a unique positive magnetoresistance effect is also seen. These observations are discussed in terms of the carrier confinement effects caused by the half metallicity of the magnetic layers. © 1999 The American Physical Society.