Exchange bias and anisotropy analysis of nano-composite Co_(84)Zr_(16)N thin films

摘要

Nano-composite Co_(84)Zr_(16)N (CZN) films were prepared by reactive co-sputter deposition. As-deposited CZN films have not shown any exchange bias effect. But annealed (390 K) and field cooled samples have shown exchange bias phenomena. The observed exchange bias is attributed to inter-cluster exchange coupling between ferromagnetic and antiferromagnetic nano-composite phase. High resolution transmission electron microscope study reveals that, the CZN films are composed of ordered and crystalline ferromagnetic Cobalt nano-clusters embedded in an antiferromagnetic matrix. X-ray diffraction confirms the poly-crystalline growth of the CZN films with a preferred fcc (622) phase formation. In-plane anisotropy of the exchange biased films was investigated by rotational magnetization curve, and the analysis shows that the magnetization reversal behaves according to the coherent rotation of the magnetic moment vector. Effectively, exchange bias effect in such single layer films could be attributed to coexisting antiferromagnetic and ferromagnetic phase within the single layer. Such single layer nano-composite films can be a possible alternative to the bilayer combination of antiferromagnetic/ferro-magnetic exchange biased films and are ideally suited for spintronics and tunnel junction applications.