Thermal Stability of Cu/Co Metaconductor and Its Millimeter Wave Applications

This work presents a study on the thermal stability of metaconductors made of copper and cobalt (Cu/Co) alternating layers in comparison with that of ones made of copper and nickel (Cu/Ni) alternating layers. Very slow anneals over several hours have been performed for both types of metaconductors. The experimental results show that after cooling down from annealing to 425 °C, Cu/Co metaconductors retain 78 % of the original magnetization, and are able to regain the original magnetization with an applied magnetic field of 50 kA/m or less. Cu/Ni metaconductors, however, lose nearly all magnetization in addition to having altered ferromagnetic properties after annealing at the same temperature. It is concluded that Cu/Co metaconductors show a superior thermal stability to Cu/Ni ones.