Thin films of organic-based magnetic materials of vanadium and cobalt tetracyanoethylene by molecular layer deposition

Abstract

Thin films of Co[TCNE]x and CoxVy[TCNE]z were grown by molecular layer deposition (MLD). Metallic cobalt (Co0) was observed in the Co[TCNE]x film which contributes to the magnetism showing a coercivity of 450 Oe at 5 K with magnetic ordering temperature above 300 K. A thin film of CoxVy[TCNE]z showed magnetic ordering temperature up to 300 K with a coercivity of 50 Oe at 5 K and 30 Oe at 300 K. The film growth was monitored using a quartz crystal microbalance (QCM), and chemical compositions were characterized by X-ray photoelectron microscopy (XPS). Compared to materials previously synthesized from solution and chemical vapor deposition (CVD) methods, thin films made in this work are smooth and pinhole-free that can be beneficial for the development of thin film devices. The chemical composition of MLD-made films and the presence of Co islands are also shown here.